Section 2: Hazard Identification and Risk Assessment - Snyder County

Snyder County Hazard Mitigation Plan Executive Summary

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Section 2: Hazard Identification and Risk Assessment

Hazard Vulnerability Analysis Methodology

Purpose and Scope

A Hazard Vulnerability Analysis (HVA) evaluates risk associated with a specific hazard and is defined by probability and frequency of occurrence, magnitude, severity, exposure, and

consequences. The Snyder County HVA provides in-depth knowledge of the hazards and

vulnerabilities that affect Snyder County and its municipalities. This document uses an all-hazards approach when evaluating the hazards that affect the County, and the associated risks

and impacts each hazard presents.

This HVA provides the basic information necessary to develop effective hazard mitigation/prevention strategies. Moreover, this document provides the foundation for the

Snyder County Emergency Operations Plan (EOP), local EOPs, and other public and private

emergency management plans.

The Snyder County HVA is not a static document, but rather, is a biannual review requiring

periodic updates. Potential future hazards include changing technology, new facilities and

infrastructure (including U.S. Route 11/15 improvements), dynamic development patterns, and demographic and socioeconomic changes into or out of hazard areas. By contrast, old hazards,

such as brownfields and landfills, may pose new threats as County conditions evolve.

Using the best information available and Geographic Information Systems (GIS) technologies, the County can objectively analyze its hazards and vulnerabilities. Assessing past events is

limited by the number of occurrences, scope, and changing circumstances. For example, ever-

changing development patterns in Pennsylvania have a dynamic impact on traffic patterns, population density and distribution, storm water runoff, and other related factors. Therefore,

limiting the HVA to past events is myopic and inadequate.

Methods of Analysis

Disaster frequency and its effects or severity are important as a basis for planning emergency

response and mitigation. Natural hazards tend to reoccur on a predictable seasonal basis,

whereas manmade or technological events tend to change over time with advancements in technology and methods of operation.

Four criteria were selected to assure a systematic and comprehensive approach to hazard

analysis:


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History: A record of past events is particularly helpful to evaluate hazards in Snyder County.

Both the frequency and severity of past events are useful to predict future events. Past records of the County’s hazards also offer valuable information when tempered with the knowledge of

preventive efforts, changes in the knowledge of preventive efforts, and advancements in

technology that may reduce the frequency or severity of such an event. Other hazards, such as terrorism, must be analyzed based on existing threat elements in and in proximity to Snyder

County.

Vulnerability: The susceptibility of a community to destruction, injury, or death resulting from a

hazard event defines the degree of vulnerability. The degree of vulnerability may be related to

geographic location as with floodplains, the type of facility or structure, or the socio-economics

of a given area. Additionally, certain population groups may be more vulnerable to some hazards because of immobility or their inability to take protective action.

Maximum Threat: The maximum threat or worst-case disaster should be considered for each

hazard. The maximum threat provides an upper boundary for the level of preparedness that may be necessary.

Probability: The probability of an occurrence in the future is another important factor to

consider when preparing for an all-hazards response. An event that occurs annually with relatively minor impact may deserve more emphasis than a major event that occurs once in 50

or 100 years.

The County relied heavily on existing data sources developed by other Snyder County departments, including the County Comprehensive Plan obtained through the Planning

Commission, the County Subdivision and Land Development Ordinance, municipal ordinances,

digital tax assessment data obtained through the Assessment Department, and Geographic Information Systems (GIS) data from the Mapping Department. In addition to the County’s

existing spatial datasets, the County EMA developed a GIS database and maps of the County’s

critical facilities, special needs populations, major employers, transportation systems, and hazardous materials facilities. Potential losses were then analyzed with FEMA’s HAZUS-MH

software.

Information was gathered from a variety of sources to develop hazard profiles, including the County’s Comprehensive Plan. State agency sources included: the PA Department of

Environmental Protection, PA Department of Conservation of Natural Resources, and the PA

Emergency Management Agency. Federal agency sources included: the Bureau of Transportation Statistics, Environmental Protection Agency (EPA), National Climatic Data

Center, and the Federal Emergency Management Agency.


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Snyder County Profile

Location and Description

Snyder County is located in the “Valley and Ridge” physiographic province of Pennsylvania and

predominately occupies the valley area between Jacks and Shade Mountains. Geographically,

this County is bordered to the east by the Susquehanna River and Northumberland County, to the south by Juniata County, to the west by Mifflin County, and to the north by Union County.

The County’s topographic features have greatly influenced past and current land uses. For

example, forested hillsides and fertile valleys provided adequate opportunities for profitable lumbering and agricultural activities. Today, Snyder County’s land area is still predominately

used for these activities. Despite the decreasing number of farms, land in agricultural uses has

continued to play a dominant role in Snyder County, occupying approximately 50 percent of thetotal land area. Most woodland is situated on steep mountain slopes and is part of state forest

holdings.

Climate and Weather

Snyder County’s climate is classified as temperate continental, characterized by large

temperature differences between summer and winter months. The County is subject to

influences by interior continental air masses, as well as by air masses from the Atlantic Ocean and the Gulf of Mexico. The weather summary shown in Table 2 - 1 provides the most

applicable, long-term weather data for Snyder County.

Table 2 - 1

Snyder County Weather Averages and Records

MonthAverage

High

Average

Low

Mean

Temperature

Average

PrecipitationRecord High Record Low

January 35o F 18o F 26o F 3.06 in. 72o F (1932) -26o F (1994)

February 38o F 19o F 29o F 2.49 in. 77o F (1985) -21o F (1934)

March 48o F 27o F 38o F 3.20 in. 87o F (1986) -6o F (1934)

April 60o F 37o F 49o F 3.60 in. 91o F (1990) 10o F (1943)

May 71o F 47o F 59o F 3.87 in. 96o F (1996) 25o F (1978)

June 79o F 57o F 68o F 4.58 in. 102o F (1952) 34o F (1926)

July 84o F 61o F 73o F 3.69 in. 105o F (1988) 42o F (1979)

August 82o F 59o F 71o F 3.78 in. 105o F (1930) 35o F (1982)

September 74o F 52o F 63o F 4.04 in. 102o F (1953) 25o F (1947)

October 63o F 40o F 51o F 3.24 in. 92o F (1941) 16o F (1976)

November 51o F 32o F 41o F 3.54 in. 84o F (1950) -5o F (1938)

December 39o F 23o F 31o F 3.00 in. 73o F (1984) -16o F (1951)

Source: The Weather Channel web site


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The weather patterns and climatic conditions of Snyder County are major risk factors. The

County’s weather extremes are the primary contributors to many of the County’s natural hazard events, including flash floods, hurricanes and tropical depressions, blizzards, tornados, drought,

severe cold and heat, high wind, hailstorms, and lightening. According to the National Climatic

Data Center, weather related events recorded from 1957 to April 2005 caused 118 deaths, 11 injuries, $52.225 million in property damage, and $500.5 million in crop damage. Some of these

events were regional disasters and their damage, such as the $500.5 million in crop damage,

reflects regional numbers. These numbers illustrate the severity of the damage that can be caused in areas, such as Snyder County, which are prone to witness extreme weather.

Weather often impedes emergency response. Because of its direct impact on mobility, severe

winter weather and flash flooding are two of the County’s biggest weather related vulnerabilities.

Population

History

Snyder County experienced a steady increase in population from 1970 - 2000. During this period, the county experienced a 4.4 percent average annual growth rate, most of which

occurred in the townships located in the eastern half of the County. From 1970 - 2000, Snyder

County’s township population grew 43.5 percent. The general population increase in Snyder County between 1990 - 2000 was ranked 37th highest among the Commonwealth’s 67 counties.

Projections

While no population projection can accurately forecast factors that might affect the population’s growth rate, future population changes depend primarily on the economic growth in the County

and the region. Population estimates, as shown in Figure 2 - 1, were developed by the

Pennsylvania Department of Environmental Protection and indicate a steady rate of growth.From 2000 - 2030, it is projected that Snyder County will experience an annual growth rate of

3.8 percent.


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Figure 2 - 1

Snyder County Population and Projections,

1970-2030

0

10000

20000

30000

40000

50000

Year

Po

pu

lati

on

County 29269 33584 36680 37546 39686 41098 41202

Townships 18709 22858 25597 26850 28952 30569 30638

Boroughs 10560 10726 11083 10696 10734 10529 10564

1970 1980 1990 2000 2010 2020 2030

Source: 1970-2000 Data from U.S. Census Bureau

2010-2030 Projections from PA DEP

Housing

History

From 1990 - 2000, the total number of Snyder County housing units increased by 9.3 percent.

This was a higher rate of increase than the population increase of 2.4 percent. When the 1980 -

2000 time period is analyzed, the annual housing growth rate was 6.7 percent. The highest increases in housing development occurred in the townships with an annual housing growth rate

of 7 percent. During this same time, housing units in boroughs increased annually by 6 percent.

According to the 2000 U.S. Census, 74 percent of all Snyder County housing in 2000 consisted of single-family detached dwellings. Multi-family units consisted of 11 percent of all housing

units. Older housing is frequently the culprit of high maintenance, heating, plumbing, and

electrical costs and problems. A majority of the housing in Snyder County was constructed before 1939. County housing development also surged in the 1970s.


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Figure 2 - 2 illustrates the average age of residential housing structures in Snyder County.

Figure 2 - 2

Age of Housing Structues in

Snyder County

1411

1822

1326

980

3032

272

687

4099

0

500

1000

1500

2000

2500

3000

3500

4000

4500

19

89

-19

90

19

85

-19

88

19

80

-19

84

19

70

-19

79

19

60

-19

69

19

50

-19

59

19

40

-19

49

1939 o

r

Ea

rlie

r

Time Period Built

Nu

mb

er

of

Str

uctu

res

Source: U.S. Census Bureau

Projections

Several factors are weighted when considering future housing quantities. These factors include

historic data and trends, vacancy rates, population projections, and the number of persons per household. As shown in Figure 2 - 3, by 2030, Snyder County expects more than 22,000

housing units within County limits. This number represents a 5.2 percent annual housing

increase from 2000 - 2030. Again, most of the growth is expected within the townships, including Center, Jackson, Penn, and Middlecreek Townships. However, Selinsgrove and

Shamokin Dam Boroughs are also projected to see continuous housing growth.


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Figure 2 - 3

Snyder County Housing Units and Projections,

1980-2030

0

5,000

10,000

15,000

20,000

25,000

Year

No

. o

f H

ou

sin

g U

nit

s

County 11,683 13,629 14,890 17,539 20,146 22,639

Townships 7,865 9,377 10,516 12,754 15,001 16,899

Boroughs 3,818 4,252 4,374 4,786 5,145 5,740

1980 1990 2000 2010 2020 2030

Sources: 1980-2000 data: U.S. Census Bureau, 2010-2030 projections: PA DEP

Land Use

Snyder County’s primary developed land use is residential. The County’s boroughs, towns, and

villages (Selinsgrove, Shamokin Dam, Middleburg, Freeburg, Beavertown, Beaver Springs,

McClure, Kreamer, Troxelville, Benfer, Paxtonville, and Penns Creek) have the highest concentrations of population and residential units. Table 2 - 2 presents the change in land-use

in Snyder County from 1992 - 2000. As of 2000, urban or built up land covered 4,276 acres,

agricultural uses covered 94,985 acres, and forest areas covered 101,453 acres in Snyder County. Agricultural land is considered to be cropland, pastures, confined feeding operations,

nurseries, and horticultural areas. Forest land is considered areas with 10 percent or more tree

coverage, and includes deciduous and/or evergreen vegetation and timberland.


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Table 2 - 2

Snyder County Land Cover Change 1992 – 2000

Land Cover Type 1992 (acres) 2000 (acres) Change (%)

Urban or Built-Up Land 3,183 4,276 34.34

Agriculture Land and Open Space 97,186 94,985 -2.26

Barren Land 119 8,058 6671.43

Forest Land 108,351 101,453 -6.37

Water or Wetlands 3,898 3,965 1.72

Sources : 1992 data: USGS NL CD, 2000 data: Penn State University

A majority of the residential development in Snyder County is occurring in the northeastern tier municipalities of Penn and Monroe Townships. Penn Township alone established 975.5

residential lots from 1989 - 1999. Monroe Township established 394 residential lots during the

same time period. Other municipalities with significant levels of residential development include Perry, Center, and Middlecreek Townships.

Commercial areas are those which sell a product or a service. Snyder County is comprised of

735 acres of commercial land, which includes urban central business districts, shopping centers, and commercial strip development. Typically, the highest concentrations of commercial

development are seen along the highest concentrations of residential development. Examples

in Snyder County include the densely populated areas in the Boroughs of Selinsgrove and Shamokin Dam.

Snyder County witnessed the improvement of 7,556 commercial properties from 1990 - 1999. A

significant amount of these improvements took place in Monroe Township (1,327 improved parcels) and Selinsgrove Borough (1,269 improved parcels). The greatest amount of

commercial development activity took place in central and eastern Snyder County.

Heavy and light manufacturing and industrial entities comprise 192 acres in Snyder County.This development is concentrated in the central and eastern portions of the County along U.S.

Route 11/15 and U.S. Route 522, as well as the Norfolk Southern rail line. This industry relies

heavily on truck and rail services, thus, manufacturing and industrial development are typically found along major transportation networks.

Selinsgrove Borough saw the highest number of improved industrial parcels from 1990 - 1999.

This Borough had 156 parcels, or 21 percent of Snyder County’s industrial activity, improved.Other municipalities that had significant industrial improvement activity include: Franklin

Township (60 parcels); Middleburg Borough (64 parcels); Freeburg Borough (60 parcels);

Spring Township (60 parcels); and Union Township (60 parcels).


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Economy

While not among the top employers in Snyder County, agriculture is still a major economic force. Snyder County is among the top 10 Pennsylvania counties in production of cantaloupes,

broilers, swine, apples, peaches, and eggs. Dairy farming is the leading agricultural enterprise

in the County, accounting for more than $20 million in annual revenues. About two-thirds of all Snyder County farms are full-time, working farms.

According to 2000 Census data, presented in Figure 2 - 4, the manufacturing industry is the

largest in Snyder County, representing 38 percent of the total workforce. Educational, health, and social services is the second largest industry sector representing 29 percent of the total

workforce. Retail trade is also a significant industry sector, as it employs 17 percent of the

workforce.

Table 2 - 3 presents the top employers for Snyder County, as listed by the Pennsylvania Bureau

of Labor and Industry. This list supports the Census data reporting of employment by industry,

as six of the major employers are in the manufacturing sector, the largest employment sector in Snyder County. Three of the major employers are in the educational services industry, the

second largest employment sector in Snyder County.

Figure 2 - 4

Employment by Industry for Snyder County, 2000

Construction,

5.8%

Retail trade, 12.6%

Arts,

entertainment,

recreation,

accommodation

and food services,

5.3%

Educational, health

and social

services, 21.4%

Manufacturing,

27.0%



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Table 2 - 3

Snyder County Major Employers

Employer Location Industry Sector

Wood Mode, Inc. Kreamer Manufacturing

Conestoga Wood Special Ties Corp. Beavertown Manufacturing

Susquehanna University Selinsgrove Educational Services

Selinsgrove Area School District Selinsgrove Educational Services

Midd-West School District Middleburg Educational Services

National Beef Selinsgrove Wholesale Trade

Wal-Mart Associates, Inc. Selinsgrove Manufacturing

Apex Homes, Inc. Middleburg Manufacturing

Penn Lyons Homes, Inc Selinsgrove Manufacturing

Professional Building Systems Middleburg Manufacturing

Source: PA Department of Labor and Industry

Geology

Snyder County is located in the tightly folded and faulted “Ridge and Valley Province” of the Appalachian Physiographic Region. This region contains sizeable areas of steep slopes,

especially along Jacks Mountain and Shade Mountain.

Geologic formations can restrict the nature and extent of surface development. It can also affect the quality and quantity of groundwater. Snyder County primarily consists of sedimentary

rock layers that cross the County from the east to west. However, portions of the County are

underlain with limestone-based geologic formations. (See Figure 2 - 5) Limestone formations are highly soluble and can create caverns and cause subsidence and sinkholes (also known as

karst topography). Karst topography is sensitive to environmental degradation. The most

severe form is the depletion and contamination of groundwater supplies.

The geologic makeup of the terrain renders the County susceptible to certain hazards, such as

radon gas. This is a naturally occurring, colorless, odorless, inert, radioactive gas that forms

from the natural decay of uranium. No individual location can be assumed to be safe unless so proven by testing.

Snyder County Hazard Mitigation Plan Hazard ID & Risk Assessment

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Figure 2 - 5

Snyder County Limestone Dolomite Deposits


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Risk Assessment

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the type…of all

natural hazards that can affect the jurisdiction.

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the…location

and extent of all natural hazards that can affect the jurisdiction. The plan shall include

information on previous occurrences of hazard events and on the probability of future hazard

events.

A comprehensive, all-hazards list of events that have or could occur in Snyder County was developed for this HVA. Appendix C provides a detailed profile of each hazard that describes

and analyzes vulnerabilities and risks each hazard has on Snyder County.

Hazards considered were:

• civil disorder

• dam failure

• drought

• fire – (urban & wildfire)

• flood

• geologic hazards – (earthquakes, landslides, sinkholes)

• hazardous materials spill

• nuclear power plant disaster

• public health emergency

• severe weather

• terrorism

• tornados

• transportation accident – (air, highway, rail, pipelines)

• utilities failure – (electric, water, gas, communications)


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Table 2 - 4 presents a comprehensive list of all natural disasters that have occurred in Snyder

County from 1963 to date.

Table 2 - 4

Snyder County Natural Disaster History

Date Hazard Event Action

Sep-05 Proclamation of Emergency - Hurricane Katrina Governor’s Proclamation

Sep-05 Hurricane Isabel/HenriGovernor's Proclamation of Disaster Emergency; Presidential

Declaration

Sep-04 Tropical Depression Ivan Presidential - Major Disaster

Feb-03 Severe Winter Storm Presidential - Disaster Emergency

Sep-99 Flash Flooding (Tropical Depression Dennis) Governor and President - Major Disaster

Sep-99 Hurricane Floyd Governor's Proclamation & President's Declaration Of Major Disaster

Jul-99 Drought Governor - Individual Assistance

Dec-98 Drought Governor's Proclamation

Jan-96 Severe Winter Storm Governor's Proclamation & President's Declaration Of Major Disaster

Jan-96 Flooding Governor's Proclamation; President's Declaration of Major Disaster

Sep-95 Drought Governor's Proclamation

Jan-94 Severe Winter Storm Governor's Proclamation & President's Declaration Of Major Disaster

Mar-93 Blizzard Governor's Proclamation & President's Declaration of Emergency

Jul-91 Drought Governor's Proclamation

Feb-78 Blizzard Governor's Proclamation

Jan-78 Heavy Snow Governor's Proclamation

Jul-77 Flash Flood None

Oct-76 Flood President's Declaration Of Major Disaster - Governor's Proclamation

Apr-75 High Winds None

Sep-75 Flood (Eloise) President's Declaration Of Major Disaster - Governor's Proclamation

Feb-74 Truckers’ Strike Governor's Proclamation

Jun-72 Flood (Agnes) President's Declaration Of Major Disaster - Governor's Proclamation

Jan-66 Heavy Snow Governor's Proclamation

Sep-63 Drought Governor's Proclamation & President's Declaration Of Major Disaster

Mar-63 Ice Jam Governor's Proclamation

Source: PEMA Web site


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The Snyder County Hazard Risk Assessment Matrix illustrated in Table 2 - 5, provides a

systematic method for assigning a risk factor to a hazard event, based on the impact and frequency of the event. Values ranging from 1-5 (1 representing a low impact, 5 representing a

catastrophic impact) were first assigned to four different vulnerability areas, based on estimated

impact: critical facility, social, economic, and environmental.

These numbers were then weighted by significance. For instance, a high amount of damage to

the population (social vulnerability) is more devastating than a high amount of damage to the

economy (economic vulnerability). Therefore, the social vulnerability is weighted at 40 percent, while the economic vulnerability is weighted at 25 percent. Based on its frequency of

occurrence, each hazard is also assigned a value ranging from 1-5 (1 representing an event

that occurs once every 31 years or more; 5 representing an annual event). The range of the risk factor score is 0-25. The example below illustrates how a hazard’s risk factor is calculated.

Risk Factor =

Frequency x [(.25 x Critical Facilities) + (.40 x Social) + (.25 x Economic) + (.10 x

Environmental)]

An example of this equation in use for a flood can be seen below:

5 x [(.25 x 1) + (.40 x 3) + (.25 x 3) + (.10 x 2)] = 12


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Table 2 - 5

EXCEL SPREADSHEET TO BE INSERTED


24


25

As illustrated in Figure 2-6, each hazard level is associated with a risk factor. Risk factors help

risk management team members differentiate credible high-hazard threats that may result in loss of life and property from less probable risks.

Figure 2 - 6

All-Hazards Risk Factor Ranking

1

1

2

2

2.8

2.85

3

3.3

4

7.5

8.25

8.4

10.2

10.6

12

9.5

7.5

7

6.6

9.5

0 5 10 15 20 25

WildfireEarthquakeLandslides

Civil DisorderSubsidence

Nuclear Power PlantTerrorism

Dam FailuresUrban Fire

TornadoDrought

TransportationHazardous Materials

Severe WeatherPublic Health Emergency

RadonPower Failure

Severe Winter WeatherHurricane/Tropical Storms

Flooding

Ha

za

rd

Risk Factor

The top three hazards in Snyder County are flooding, hurricanes and tropical storms, and

severe winter weather, respectively. While the HVA focuses on the top three hazards, the

analysis illustrates how often these hazards are inter-related, causing or being caused by other hazards. The vulnerability of critical facilities, social, economic, and environmental factors are

analyzed by the threat each hazard proposes. A detailed description of all hazards is found at

Appendix C, Hazard Profiles.

Vulnerability Assessment: Identifying Assets

Requirement §201.6(c)(2)(ii): [The risk assessment shall include a] description of the

jurisdiction’s vulnerability to the hazards described in paragraph (c)(2)(i) of this section. This

description shall include an overall summary of each hazard and its impact on the community.

Critical Facilities Vulnerability Assessment

Location identification of critical facilities in the County is crucial to assessing their vulnerability to hazards. Table 2 - 6 lists the locations of the critical facilities in Snyder County. This

knowledge is invaluable at the occurrence of a hazard. The facilities that lie in the floodplain are

all housed in one structure at 713 Bridge Street, Selinsgrove, PA. GIS provides an in-depthillustration of all critical County infrastructure in the floodplain.


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Table 2 - 6

Snyder County Municipal Critical Facilities

Name Location Located in Flood Plain

Beaver Township Municipal Building Beavertown No

Beavertown Borough Office Beavertown No

Center Township Municipal Building Center Township No

Chapman Township Municipal Building Port Trevorton No

Jackson Township Municipal Building Jackson Township No

McClure Borough Office McClure No

Middleburg Borough Office Middleburg No

Middlecreek Township Building Kreamer No

Monroe Township Building Selinsgrove No

Penn Township Municipal Building Penn Township No

Perry Township Municipal Building Mt. Pleasant Mills No

Selinsgrove Borough Office Selinsgrove No

Shamokin Dam Borough Office Shamokin Dam No

Spring Township Municipal Building Beaver Springs No

Union Township Municipal Building Port Trevorton No

Washington Township Municipal Building Washington Township No

West Perry Township Municipal Building Richfield No

Snyder County Court House Middleburg No

Snyder County Conservation District Middleburg No

Farm Service Agency (FSA) Middleburg No

Natural Resources Conservation Service (NRCS) Middleburg No

Snyder County Sheriff Middleburg No

Snyder County Emergency Services Penn Township No

Penn Valley Airport Authority Selinsgrove No

Snyder County Prison Penn Township No

Snyder County Housing Authority Middleburg No

Children and Youth Services Selinsgrove Yes

Pennsylvania Career Link Building Selinsgrove Yes

Bureau of Workforce Development Partnership Selinsgrove Yes

Central Susquehanna Intermediate Unit Selinsgrove Yes

Central Susquehanna Opportunities, Inc. Selinsgrove Yes

Office of Vocational Rehabilitation Selinsgrove Yes

Snyder County Assistance Office Selinsgrove Yes

Sun Family Planning/WIC Selinsgrove Yes

Snyder County Waste Management Selinsgrove Yes

Union/Snyder Community Action Team Selinsgrove Yes

Pennsylvania Career Link Selinsgrove Yes

Midd-West School District Office Middleburg No

Selinsgrove Area School District Office Selinsgrove No

Source: Snyder County 2006 Local Government Officials Directory


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Flooding

Critical facilities consist of municipal buildings, pumping stations, electricity transmitters, and first responder facilities. Their vulnerability to flooding is low, because such facilities should not

be located in the floodplain. However, secondary flooding effects can have a great and

deleterious affect on critical facilities. Flooding can also lead to further hazards, such as power failures, hazardous materials spills, and transportation infrastructure closures. These secondary

effects can have significant impacts on the vulnerability of critical facilities.

The National Flood Insurance Program (NFIP) establishes minimum floodplain management criteria. Property owners in the floodplain should comply with land use floodplain regulations for

their communities. The NFIP’s Community Rating System (CRS) discounts flood insurance

premiums in communities that establish floodplain management programs that go beyond NFIP minimum requirements. Under the CRS, communities receive credit for more restrictive

regulations, acquisition, relocation, or flood proofing of flood-prone buildings, preservation of

open space, and other measures that reduce flood damages or protect the natural resources and functions of floodplains.

The structures in a floodplain include those based on a point within a two-dimensional (longitude

and latitude) plane. This data, however, does not include attribute information for first-floor flood elevations; this information is essential to assess the base flood elevation’s impact on the

county’s infrastructure. As a result of this limitation, the estimates are likely overstated, but to

what degree the potential losses are overstated can not be determined.

Hurricane/Tropical Storm

Snyder County’s critical facilities are moderately impacted by hurricanes or tropical storms. This

strong weather can cause great physical damage to property and can make it difficult for County personnel to travel to these critical facilities, if necessary.

Secondary effects, such as power outages, flooding, and disruptions or closings of

transportation infrastructure can also affect critical facilities operations, as previously discussed.

Severe Winter Weather

Severe winter weather also poses a moderate impact on critical facilities in Snyder County,

largely due to the potential for power outages and closings of transportation infrastructure.Prolonged periods of cold weather can lead to widespread closings of some public facilities,

such as schools. Power outages are an important secondary affect to consider when assessing

vulnerability to severe winter weather. The loss of power for extended periods of time can cause a loss in communications and hinder essential needs, such as home and business

heating.


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Social Vulnerability Assessment

A Social Vulnerability Assessment identifies areas of special needs populations, which consist of citizens with disabilities, people over age 65, persons living alone, and others. This

population must be identified and targeted in successful hazard mitigation planning to prepare

the County to safely evacuate these citizens or bring them the special supplies they may need to survive during a hazardous event. Table 2 - 7 presents an overview of the special needs

populations in Snyder County. The size of the elderly population, householders living along,

renters, and non-English speaking residents have all increased by over 10 percent between 1990 - 2000. With the size of the special needs population growing in Snyder County, it is vital

that planning considers the needs of these population segments.

Table 2 - 7

Special Needs Population in Snyder County

1990 2000 % Change

Total Population 36,680 37,546 2.4%

Urban Population 5,384 10,835 101.2%

Rural Population 31,296 26,711 -14.7%

Elderly (65+) 4,616 5,275 14.3%

Householder Living Alone 2,576 3,052 18.5%

Renter Occupied Dwellings 2,916 3,211 10.1%

Non-English Speaking Population 2,552 2,828 10.8%

Population Living in Poverty 3,789 3,495 -7.8%

Institutionalized Population 995 897 -9.8%

Disabilities (ages 16+) -- 11,235 --

Sensory Disability -- 1,073 --

Physical Disability -- 2,522 --

Mental Disability -- 1,525 --

Self-Care Disability -- 888 --

Go-Outside-Home Disability -- 2,385 --

Employment Disability -- 2,842 --



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Flooding

Flooding presents a high social vulnerability to Snyder County, because it puts the entire population at risk. High floodwaters can devastate homeowners with both property damage and

loss. Secondary effects of flooding also present vulnerability hazards. Power loss can leave

homes without heat for extended periods of time. Transportation infrastructure can also be disrupted, often leaving citizens and businesses without essential goods and services.

Hurricanes/Tropical Storms

The County’s social vulnerability to hurricanes and tropical storms is also high. These storms, along with secondary flooding, can cause significant property damage. Power outages and

disruption of basic services all can have lasting effects.


Snyder County is susceptible to an array of winter weather. Social vulnerability associated with

severe winter weather is high and can cause business and school closures, aggravated by

dangerous travel. Human exposure to prolonged storms can result in hypothermia and other illnesses, especially among the elderly and young children. Secondary affects include flooding,

power outages, and roadway accidents.

Economic Vulnerability Assessment

A community’s economic vulnerability may be the most important factor to consider when

assessing the effects of certain hazards in Snyder County. Loss of income or loss of jobs

through business interruption or closures can devastate a community.

This analysis determines the hazard vulnerabilities of economic centers. It is essential to

identify the potential negative impacts the greatest hazards may have on the County economy.

This enables the prioritization of potential hazard mitigation strategies to eliminate or reduce the risks these hazards present.

While the agriculture industry sector is not a major employer in Snyder County, it is important to

remember its key role. Snyder County is among the top 10 Pennsylvania counties in the production of cantaloupes, broilers, swine, apples, peaches, and eggs. Dairy farming is the

leading agricultural enterprise in the County, accounting for more than $20 million annually.

About two-thirds of all Snyder County farms are full-time, working farms.

Flooding

The Snyder County economy has a high vulnerability to flooding. The potential impacts caused

by this hazard can lead to long-term economic disruption, especially for small businesses.


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Flooding can ruin the structure of the business, along with the merchandise or equipment in the

building.

Secondary affects of flooding can also have devastating effects on the Snyder County economy.

Power outages and disrupted transportation infrastructure can paralyze business operations

and have a long-lasting effect on the local economy.

One of Snyder County’s top employers, Wood Mode, Inc. located in Kreamer, PA, resides along

Middle Creek. While no first-floor flood elevation data is available, this facility may be at risk for

potential losses due to flooding.


Snyder County has a high economic vulnerability to hurricanes and tropical storms. This severe

weather can halt business temporarily, primarily through secondary effects, such as flooding and power loss.


The economic vulnerability to severe winter weather in Snyder County is also high. Prolonged periods of snow and extreme temperatures can hinder travel to and from economic centers in

the County. Secondary affects also play a crucial role in the severity of this hazard. Power loss

can shut down businesses for lengthy periods of time. Extended periods of cold temperatures expand businesses’ operating expenses with increased heating and snow removal costs. When

warmer weather arrives, accumulating mounds of snow can melt, resulting in flood hazards.

Environmental Vulnerability Assessment

An Environmental Vulnerability Assessment identifies environmental resources that may be

impacted by hazards and their secondary effects, such as toxic releases or hazardous spills.

The location, identification of hazardous materials, and associated dangers with each of the Snyder County SARA facilities is essential to knowing the potential impact these facilities may

have on the County.


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Table 2 - 8 lists the SARA facilities located in Snyder County and tells whether or not they

reside in the floodplain.

Table 2 - 8

Location of SARA Facilities in Snyder County

Name of Facility LocationIn Flood

Plain

A Patch Orchards Middleburg, PA No

Beaver Springs Municipal Authority Wastewater Treatment Plant Beaver Springs, PA No

Eastern Snyder County Regional Wastewater Treatment Facility Selinsgrove, PA Yes

Krartzerville Municipal Authority Water Treatment Facility Selinsgrove, PA No

Kreamer Municipal Authority Wastewater Treatment Facility Kreamer, PA Yes

McClure Municipal Authority Wastewater Treatment Facility McClure, PA No

Middleburg Borough Wastewater Treatment Facility Middleburg, PA No

Middleburg Borough Water Treatment Facility Middleburg, PA No

Farmland National Beef Packing Company Hummels Wharf, PA No

Penns Creek Municipal Authority Wastewater Treatment Facility Penns Creek, PA No

Penn Township Water Treatment Facility Selinsgrove, PA No

Sunbury Generation L.L.C. Shamokin Dam, PA Yes

Sears Auto Center Selinsgrove, PA No

Borough of Selinsgrove Water Treatment Facility Selinsgrove, PA No

Selinsgrove Community Pool Selinsgrove, PA No

Shamokin Dam Borough Water Treatment Facility Shamokin Dam, PA No

Wood Mode, Inc. Kreamer, PA No

Flooding

Flooding presents moderate environmental vulnerability to Snyder County, stemming from the

possible spill of hazardous materials as a secondary effect of flooding. For example, flooding

can result in contamination (a secondary hazard) when raw sewage, animal carcasses, chemicals, pesticides, or other hazardous materials are suspended and transported through

sensitive habitats, neighborhoods, or business settings. Events such as these require major

clean up and remediation efforts.


Snyder County also faces moderate environmental vulnerability from hurricanes and tropical

storms. With high winds and heavy rain produced by these storms, some level hazardous materials spills are likely to occur as a result of traffic accidents or from secondary affects such


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as flooding. The severity of the environmental damage largely depends on a storm’s strength

and duration.


The environmental vulnerability of Snyder County is low in relation to severe winter weather.

Snyder County’s location in central Pennsylvania makes it susceptible to blizzards, heavy snowfall, heavy fog, hail, heavy rain, high winds, ice storms, and temperature extremes.

However, most of these natural hazards do not pose a direct threat to the environment.

Secondary effects of severe winter weather can cause environmental hazards. Most notably, flooding after the spring thaw can contaminate ground water via hazardous material spills.

Similarly, severe winter weather can lead to traffic accidents and hazardous material spills from

transportation vehicles carrying these materials.

Vulnerability Assessment: Estimating Potential Property Loss

Requirement §201.6(c)(2)(ii)(A): The plan should describe vulnerability in terms of the types

and numbers of existing and future buildings, infrastructure, and critical facilities located in the

identified hazard area.

Requirement §201.6(c)(2)(ii)(B): [The plan should describe vulnerability in terms of an] estimate

of the potential dollar losses to vulnerable structures identified in paragraph (c)(2)(i)(A) of this

section and a description of the methodology used to prepare the estimate.

Flooding is the most significant hazard in Snyder County, both directly and secondarily. The

estimation of potential loss in this assessment focuses on the monetary damage that could result from flooding. The potential estimated loss in property from flood damage was

determined for each municipality and the entire County. The following primary datasets are

included in the floodplain analysis: ERRI Floodplain (1996); Snyder County Tax Parcel Boundaries (2005); Snyder County Tax Assessment Database (2006); and Snyder County

Structures (2005).

Potential estimated losses were calculated by first determining the number of structures completely situated in the floodplain. The structures had no assessed value or size attribute

information, so a new layer was created that includes all tax parcels with structures contained in

the floodplain. The new layer allowed assessed property values and the acreage to be calculated for parcels with structures completely in a floodplain.

The absolute total and assessed value and acreage was then calculated from the Snyder

County Tax Assessment Database for each of its 21 municipalities. The data was further divided by property class, allowing the total assessed value and acreage for each type of class

in each of the municipalities.


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The end result of the analysis will allow reasonable determinations of the potential estimated

loss for each type of property class in each of the 21 municipalities. The total acreage of parcels with structures completely engulfed by the floodplain was also calculated for each class

and each municipality. The results are presented in Table 2-7. The estimated losses can only

be presented as potential, based on the random occurrence of flood conditions and limited data.The structures in a floodplain include those based on a point within a two-dimensional (longitude

and latitude) plane. This data, however, does not include attribute information for first-floor flood

elevations, which is essential to assess the base flood elevation’s impact on the County’s infrastructure. As a result of this limitation, the estimates are likely overstated, but to what

degree the potential losses are overstated can not be determined.


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Table 2 - 9

Estimated Potential Loss


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Table 2 - 9

Estimated Potential Loss, continued


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Table 2 - 9



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Table 2 - 9



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Table 2 - 9



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Vulnerability Assessment: Analyzing Development Trends

Requirement §201.6(c)(2)(ii)(C): [The plan should describe vulnerability in terms of] providing a

general description of the land uses and development trends within the community so that

mitigation options can be considered in future land use decisions.

Overview

An examination of recent development trends should help to identify and anticipate future

vulnerabilities to hazards which may affect the County’s growth and development. The Snyder

County Comprehensive Plan (2001) provides significant information on land use and development trends and was instrumental in the creation of this section.

Improvements to the County’s transportation system in recent decades have provided Snyder

County residents with greater mobility and access to regional employment centers. Significant increases in residential, commercial, and industrial land uses have also resulted and impacted

outlying areas with high-density industrial development. This is evidenced in the County’s

eastern tier municipalities, which have experienced the greatest growth and development, primarily stemming outward from U.S. Routes 11/15 and 522.

To conduct a thorough analysis, residential growth activity was analyzed utilizing 2000 Census

data. Next, industrial and commercial growth activity from 1990-1999 was analyzed usingbuilding permit data inventoried through the comprehensive planning process. Finally,

impervious surface coverage data from 1985 and 2000 was analyzed to determine static

development trends and developing areas in relation to flood plain proximity. This combined information produces a more accurate depiction of the County’s historical growth trends.

Residential Improvements

As indicated in the Snyder County Comprehensive Plan, residential land development activity in recent years was experienced by all municipalities. However, the level of activity increased

from the western to eastern tier municipalities. This is indicative of a migratory growth pattern

stemming east to west outward from major transportation corridors in the eastern portion of the County. Public infrastructure improvements and expansion westward from this corridor has

facilitated the increased residential improvements in the County’s rural based, eastern tier

municipalities. Most notably, Monroe Township and Selinsgrove Borough experienced the greatest number of improved residential parcels. The County’s total residential development

activity steadily increased from 10,530 improved parcels in 1990 to 11,349 in 1999,

approximately an eight percent increase overall or an average annual percentage increase of approximately one percent. Monroe Township experienced the highest number of improved

residential parcels with 15,173, or about 13.9 percent of the total. However, Selinsgrove


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Borough also experienced a high number of improved residential parcels, with 12,038 or about

11.0 percent of the total.

Industrial Development Activity

Selinsgrove Borough experienced the greatest number of improved industrial parcels during the

period 1990-1999. During this period, the borough had 156 improved industrial parcels, which comprise 21.0 percent of the County’s total activity. Other municipalities that experienced a

significant level of industrial improvement activity were: Franklin Township (70); Middleburg

Borough (64); Freeburg Borough (60); Spring Township (60); and Union Township (60). In contrast to the residential development trends, the County’s greatest level of industrial

development activity (with the exception of Selinsgrove Borough) was concentrated in the

central and western portions.

Commercial Development Activity

During the period 1990-1999, Snyder County experienced 7,556 improved commercial parcels,

with the greatest number of improvements occurring in Monroe Township (1,327) and Selinsgrove Borough (1,269). Combined, these municipalities comprised 34.3 percent of the

County’s total improved commercial parcels. Overall, the greatest level of commercial

development activity occurred in the central and eastern tier municipalities. From 1990-1999,the level of improved commercial parcels increased steadily from 736 to 794, an overall

increase of approximately eight percent or an average annual percentage increase of one

percent. Overall, these analyses indicate that the majority of Snyder County’s development activity during this time period occurred in the rural-based, eastern tier municipalities in

proximity to existing public infrastructure and major transportation corridors, including U.S.

Routes 11/15 and 522.

Projected Housing Growth

Projections of the number of households can be used to estimate future utility, facility, and

service needs. Projections can also help to determine the likelihood of where new housing construction will take place, and the amount of area absorbed by residential development in the

next 20 years. Snyder County is expected to have approximately 19,000 occupied housing

units in 2020. This represents an average annual increase of 10.1 percent for the period 1990-2020, which is less than the increase of 15.4 percent experienced for the period 1970-1990.

The greatest percentage increases in total housing units occurred primarily in the eastern tier of

the County, specifically, in Penn, Jackson, Center, Middlecreek, and Washington Townships.


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Impervious Surface Coverage

A comparison of impervious surface coverage data1 provides another method of detecting change in Snyder County’s growth and development patterns. Impervious surface data

estimated from Thematic Mapper data using algorithms developed by Dr. Toby Carlson at

University Park, Pennsylvania, was originally generated to support hydrologic investigations.This data is also useful for assessing urbanization and development patterns over time.

Impervious surfaces primarily reflect the urban and built environments that include rooftops,

sidewalks, roads, and parking lots.

By examining impervious surface coverage data, recent development trends in relation to flood

plain proximity can be ascertained. This may generate recommendations to examine certain

areas in more detail, since data on several boroughs and municipalities indicate some development in flood plains may have taken place.

Selinsgrove Borough

The majority of impervious surface coverage development since 1985 has primarily been in the western portion of the Borough, outside of the flood plain. However, 2000 data indicates some

development has occurred in the extreme southern end of the Borough and more importantly,

on the far eastern side, potentially in the Susquehanna River flood plain. Additionally, this data indicates sparse development in the extreme northern end of the Borough at the confluence of

the Penns Creek and Susquehanna River flood plains. This has been identified as a maximum

threat area for Selinsgrove Borough, because of the frequency and potential impact of flooding.

Hummels Wharf

Hummels Wharf has experienced sporadic development, with the greatest concentrations in the

southern and western portions of town. Of greatest concern are two areas of development that have occurred from 1985-2000. The first is a dense concentration in the southern portion of

town, just north of the junction of U.S. Routes 11 and 522. The second area is along the

northeastern portion of town and stretches north to south along the boundary of the Susquehanna River flood plain. Both these areas are relatively concentrated and should be

examined closer to determine proximity to the Susquehanna River flood plain.

Shamokin Dam Borough

Shamokin Dam has experienced sporadic impervious surface development throughout the

Borough. Data from 1985 and 2000 show significant development efforts in the eastern portion

of the Borough along the Susquehanna River flood plain. Of particular concern is the data from

1Pennsylvania State University, 1985 and 2000


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2000, which indicates continued sporadic development along the flood plain. There are dense

pockets of development that run north to south along the Borough’s boundary with the Susquehanna River flood plain.

Middleburg Borough

Middleburg has had a surge of impervious surface development since 1985. While the bulk is around the southern edges and outside of the Middle Creek flood plain, 2000 data indicates

isolated and sparse development in the northern, northwestern, and northeastern portions of the

Borough in close proximity to the Middle Creek floodplain.

McClure Borough

McClure has also experienced significant impervious surface development, primarily focused on

the outer fringes of town and in the southwestern portion of the Borough. The sporadic development in the northern portion of the town along South Branch Middle Creek is of minor

concern. While not anticipated to result in a severe impact, the segment of northern

development along the South Branch Middle Creek still remains in the flood plain and should be examined closer.

Beaver Springs

Beaver Springs has experienced areas of dense impervious surface coverage development.The area of greatest concern is in the vicinity of the intersection of PA S.R. 235 and U.S. Route

522 in the northern portion of the town, and an extension running east to west along U.S. Route

522. Both these areas lie abreast of, or potentially encroach on, the Middle Creek flood plain.

Beavertown Borough

Beavertown’s growth primarily has been centered along U.S. Route 522. Of minor concern are

areas of sporadic development in the western portion of the town, which may lie along a Middle Creek tributary flood plain.

Penns Creek

Penns Creek’s development has largely occurred in the northwestern portion of town and outside the flood plain. However, there are areas of sporadic development in the southern

portion of town along S.R. 104, which may be in the Penns Creek floodplain.

Freeburg

Freeburg’s development efforts have been centered along S.R. 35 between two tributaries that

feed Middle Creek Lake and ultimately, the Susquehanna River. While not anticipated to be a


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major concern, data indicates some recent development toward the town center and

southeastern portion of town may be along a tributary flood plain and should be examined closer.

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Snyder County Hazard Mitigation Plan Glossary of Acronyms & Definitions

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Future Land Use

This examination of the County’s recent development trends has shown continued growth in the outlying rural municipalities, outside Selinsgrove and Shamokin Dam Boroughs. This leads to

the conclusion that suburban growth continues to be the primary development pattern in the

County. The analysis of impervious surface coverage data has indicated recent development efforts which may have encroached on several flood plains. A closer examination of these

areas is highly recommended to ascertain actual proximity to known flood plains, and whether

this development could lead to repetitive losses.

This development pattern is due in part to the strategy outlined in the Snyder County

Comprehensive Plan, which states that the County is directing new development to areas that

have supportive infrastructure. This focus protects the County’s outlying rural and natural resource areas, and controls growth impact on the County’s rural and environmentally-sensitive

areas. The County is accomplishing this by identifying potential growth areas that are serviced

by public sewer, public water, and transportation infrastructure. Future growth should be directed to these areas to protect and preserve important natural resources, direct growth and

development to the appropriate locations, and facilitate coordinated planning at all levels of

government. Growth areas are spatial delineations where development at higher densities is encouraged and infrastructure to serve such development is provided and planned. Ultimately,

this strategy will help the County achieve its goals of: strengthening economic centers;

strengthening village centers to serve as mixed use communities; preserving the open, rural character of Snyder County; and restricting development in areas with significant natural

resources, including stream corridors, woodlands, wetlands, groundwater recharge areas, steep

slopes (>25%), and prime agricultural soils.

Multi-jurisdictional Risk Assessment

Requirement §201.6(c)(2)(iii): For multi-jurisdictional plans, the risk assessment mus t assess

each jurisdiction’s risks where they vary from the risks facing the entire planning area.

The top three hazards identified for Snyder County are flooding, hurricanes and tropical storms,

and severe winter weather. Of these, only flooding areas affect individual locations. The

others, like the majority of the identified hazards, are regional and affect more than one jurisdiction simultaneously.

Flooding occurs along the creek and river banks in Snyder County. Most notably, communities

along the Susquehanna River and Penns Creek are prone to flooding. The eastern tier municipalities of Monroe, Penn, Union, and Chapman Townships, and the Boroughs of

Shamokin Dam and Selinsgrove experience the maximum threat of flooding from the

Susquehanna River. Center, Jackson, Middlecreek, Union, and Penn Townships are at maximum threat of flooding from Penns Creek. The maximum threat for Snyder County exists

Snyder County Hazard Mitigation Plan Glossary of Acronyms & Definitions

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at the confluence of the Susquehanna River and Penns Creek, along the U.S. Route 11/15

transportation corridor in the vicinity of Selinsgrove and Shamokin Dam. Consequently, these dense population centers and surrounding residential communities would also experience the

greatest impact.

Of the other hazards identified, hazardous material spills are often a centralized hazard occurring along major transportation routes. Hazardous material spills mostly occur along

major transportation routes. Within Snyder County, S.R. 104, 35, U.S. Route 522 and U.S.

Route 11/15 are most vulnerable.

Similarly, dam failures are likely to occur where high hazard dams are located. The

municipalities that contain these high-hazard dams face the maximum threat of a significant

dam failure. Kern Run Dam in Beavertown, Walker Dam in Troxelville, and Faylor Lake Dam in Beaver Springs, are all high-hazard dams requiring emergency action plans.

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Section 2: Hazard Identification and Risk Assessment - Snyder County

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