Snowflakes – Pretty but Dangerous

Snowflake type depends on temperature

30 – 20 °F needles

Snowflake type depends on temperature

20 – 0 °F dendrites

Snowflake type depends on temperature

0 to -20 °F hexagonal plates

Snowflake type depends on temperature

-20 and colder hexagonal columns

Mythbuster: Does 10 Inches of Snow Equal 1 Inch of Rain?

The quick answer: sometimes but you have to assume that the storm is all snow.

Temperature degrees F Snow Ratio in Inches35 – 40 5:130 10:125 15:120 20:1

Winter Storms

SNOW!

Don’t forget to close your windows

Blizzard

• winds blow at 35 mph or higher

• visibility is reduced to ¼ mile or less for 3 hours or more

Does it have to be snowing for it to be a blizzard?

a. yes

b. no

How are winter storms created?

• Two air masses of different temperatures and moisture levels meet along a stationary front.

• In North America, cold, dry, Canadian air moves south and interacts with warmer, moist air moving north from the Gulf of Mexico to create a winter storm.

How are winter storms created?

• An area of lower pressure develops along the front. This creates winds that blow from high to low.

• As air moves toward the low, it has nowhere to go but up into the colder regions of the atmosphere where condensation occurs.

• To the north of the storm, where temperatures are colder, snow falls.

Rain or Snow?

Freezing Rain

(St. Joseph’s

lighthouse)

March 13, 1993

Winter Storm of 1993

All east coast air ports were closed.

Georgia

December 2001

New York City 2006

The official instrument – the ruler!

New Jersey 2006

Storm Duration

Over North America, strong winds blowing from west to east usually move a winter storm quickly across the continent. That's why a winter storm rarely lasts more than a day in one area.

One exception to this rule occurs downwind of major bodies of water such as the Great Lakes.

Lake Effect Snow

Lake Effect Snow

• If a strong, cold wind blows over a great length of unfrozen water, the air acquires a lot of moisture. This moisture turns into heavy snow when it reaches land.

• These "lake-effect" snowstorms can last for many days and dump huge amounts of snow.

• A lake-effect snowstorm in November 2000 dumped 25" of snow in 24 hours on Buffalo, NY. At the storm's peak, it dumped 3" of snow per hour!

Buffalo, NY 1977

Top 10 NJ Snow Storms since 1800

• Year Inches County• 1899 34 Cape May• 1831 30 Cape May• 1947 30 Monmouth• 1996 30 Burlington• 1925 28 Essex• 2000 26 Morris• 1888 25 Union• 1958 25 Sussex• 1805 24 Essex• 1961 24 Hunterdon

Nor’easters

• named for the winds that blow in from the northeast and drive the storm up the east coast

• occur in the eastern United States from October to April (those that occur early or late in season when trees are in leaf can be particularly bad)

• dump heavy amounts of rain or snow, produce hurricane-force winds, create high surf that causes severe beach erosion and coastal flooding

Nor’easters• There are two main components to a Nor'easter:

– A Gulf Stream low-pressure system with counter-clockwise winds off the southeastern coast of the US gathers warm air and moisture from the Atlantic. Strong NE winds at the leading edge of the storm pull it up the east coast.

– An Arctic high-pressure system with clockwise winds blows down from Canada and collides with the Gulf Stream low.

There are two types of Nor'easters:

– Offshore forming - These are the storms you hear about in the news. Metropolitan areas such as Washington D.C, Philadelphia, New York City and Boston are hard hit. Eventually, the system moves far enough north that the Canadian jet stream pushes it off the coast.

– Onshore forming - These storms are less exciting than the offshore-forming storms. They have gusting winds and mostly rain.

Satellite image of the intense nor'easter

responsible for the blizzard of 2006. Note the

hurricane-like eye at the center.

The Winter of 2006 – 2007

• 14 major storms, 2 more than ever before• Only FL and CA escaped the effects• Lasted 6 months, $6.8 billion in losses and

costs to respond, caused 214 deaths• 6 of the 14 storms were classified as

“catastrophes” by the insurance industry• The effects were most intense in five

sectors of the economy – property, power, business, transportation, and government.

The Winter of 2006 – 2007

• The 2 worst storms of the year –– The storm that hit the Plains and Midwest was

1,085 miles long and 141 miles wide. It covered 152,600 square miles. This was 3.5 times larger than the average snowstorm.

– The Valentine’s Day storm that hit the NE covered 186,200 square miles, 4.5 times larger than the average. It contained a band of freezing rain 80 miles wide.

The Winter of 2006 – 2007

• Why this season was so bad:– Storms occurred early and late in the season

resulting in severe damage to trees and shrubs because they were still in leaf. In turn, the trees caused damage when they fell.

– Storms occurred in areas where they are infrequent and local officials struggled to respond.

– Four of the storms were extremely large.– Storms hit urban areas.

Dolan-Davis Wave Power Indexproposed rating scale for Nor’easters

• Sea waves generated by a Nor’easter govern the storm’s coastal impact.

• The index is computed by multiplying a storm’s duration and wave height.

• Class 1, very common weak systems, that might last 4 hours with 6.6 feet waves, minor beach erosion and little or no property damage.

• Class V, very rare extreme systems, that might last 4 days or longer with 23 foot waves that produce extreme beach erosion and cause regional property damage.

Weather.com gets in trouble with theNational Weather Service

Winter Storm Names 2012 – 2013Athena Helen Orko VirgilBrutus Iago Plato WaldaCaesar Jove Q XerxesDraco Khan Rocky YogiEuclid Luna Saturn ZeusFreyr Magnus TritonGandolf Nemo Ukko

Ice storm• A severe ice storm hit Missouri, Kansas,

Nebraska, Iowa and Illinois.

• Ice covered an area the size of California.

• Missouri declared an emergency and put the National Guard on alert.

• Thousands of people slept in airports due to delayed and cancelled flights.

• The airport in Tulsa, OK had no electricity.

Ice Storm – December 2007

University of Oklahoma

Utility crews struggle to restore power to over 1 million homes. In Oklahoma, this was the worst blackout in state history.

Winter of 2013 - 2014

This is only one of the 20 winter storms for which the Off ice of the New Jersey State Climatologist collected data and created maps.

Winter of 2013 - 2014

Winter of 2013 - 2014• Mid-Atlantic, NE and New England temperatures averaged

below normal • Jan and Feb were coldest months compared to average• Dec and Feb were wettest months, with well above normal

precipitation• even distribution of precipitation up and down the East

Coast of between 12 and 14 inches• all stations saw above average snowfall for the period• Philadelphia to New York City corridor saw highest totals

compared to average• Dec-Feb, Philadelphia saw over 300% of typical snowfall

accumulation • many locations doubled or tripled their snowfall compared to

last year!

What is the number one cause of deaths during winter storms?

Winter Storm Dangers

• Traffic accidents is #1!

• Heart attacks while shoveling

• Hypothermia from exposure to cold

• Frost bite due to wind chill

Why is ice slippery?

• Weight adds pressure that makes ice melt.

• People and cars are heavy so they create a thin layer of water between the ice and the shoe or tire.

Winter Storm Safety• Find shelter; stay dry; cover all skin; get

out of the wind• Build a fire surrounded by rocks• Do not eat snow; melt it first• Stay in your car with window open for air• Make sure exhaust pipe is not blocked• Tie red flag to car• Exercise to stay warm• Run the engine for 10 minutes each hour

Avalanches

• An avalanche is a mass of tumbling snow.

• Can travel at up to 200 mph

• Destroy everything in their path

• 1200 in US each year

The Children’s Blizzard 1888

What made the storm so deadly was the timing (during work and school hours), the suddenness, and the brief spell of warmer weather that preceded it. The very strong winds and the powdery nature of the snow reduced visibilities on the open plains to zero. People ventured from the safety of their homes to do chores, go to town, or attend school. As a result, thousands of people—including many schoolchildren—got caught in the blizzard. The death toll was 235.

1888

The Children’s Blizzard 1888

• Lois Royce found herself trapped with 3 students in the schoolhouse. By 3 p.m., they had run out of heating fuel. Her boarding house was only 82 yards (75 m) away, so she attempted to lead the children there. However, visibility was so poor that they became lost and the children, two nine-year-old boys and a six-year-old girl, froze to death. The teacher survived, but her feet were frostbitten and had to be amputated.

• Etta Shattuck, a 19 year old teacher, got lost on her way home She sought shelter in a haystack but was trapped there until her rescue 78 hours later. She died on February 6 due to complications from surgery to remove her frostbitten feet and legs.

• In South Dakota, two men tied a rope to the closest house and headed for the school. There, they tied off the other end of the rope, and led the children to safety.

• Minnie Freeman safely led 13 children from the school to her home, one half mile (800 m) away. She took them to the boarding house she lived at about a mile away and all of her pupils survived.