The Use of NWS Frost Depth Gauges to acquire

frost depth information in Wisconsin

34 Frost depth gauge sites. 29 at COOP and UCOOP sites – 5 at WIS-DOT sites

Purpose, benefits, drawbacks to frost depth gauge program

– Purpose – to secure accurate and reliable frost depth information on a systematic basis from trained observers.

– Benefits – more reliable data gathering method than trying to secure information from grave diggers, utility companies, etc. Low cost, low maintenance, observers like them. Data goes into AWIPS database through WXCODER in SHEF format. SHEF code is GD.

– Drawbacks – no known supply of gauges, gauges have to be built locally, can be difficult to install.

Source of supplies, costs

• Components to build frost depth gages and their covers can be purchased at local hardware stores - PVC pieces, clear plastic tubing, etc. Complete list of components, diagram, and construction details in Mark Walton’s 1998 paper “Flood Forecasting & Frost Depth”.

• Total cost of components to build 1 frost depth gage and a cover- $20.00 - $30.00

My strategy for installation

• Have 3 lengths of frost depth gages available: 3 ft, 4 ½ ft, 6 feet.

• -Goal is to install a 6 foot gauge, if possible

• - If unable to install a 6 foot gauge due to obstructions, etc., then install a shorter one.

Tools used to install- power soil auger

Tools used to install-manual soil auger

Frost depth gage being installed near other NWS equipment

Frost depth gage installed – with PVC cover. Note: flagged location

marker

Frost depth gage with other NWS equipment

Training the observer how to read frost depth gage

Example of observer reading frost depth gauge

Instructions for frost depth observers• Nov. 1 - April 30 - report frost depth (depth of frost penetration) twice a week normally

on Monday mornings (or the next available day) and Thursday mornings (or the next available day). If there is no frost penetration, report 0 inches of frost depth. Frost depth is reported to the nearest whole inch. If you estimate the frost depth penetration is 2.5 inches, report 3 inches.

• • Jan. 1 – April 30 – report frost depth thawed (in addition to frost depth - on same

schedule as above). If there is no frost depth thawed, report 0. Only report frost depth thawed if you have 1” or more. Use same rounding off to next whole inch guidelines as stated above.

• If you have to shovel snow away from the frost depth gage to get to it, please replace the snow approximately the way you found it…to simulate the natural conditions in the area of the gauge.

• If you are unable to use Weather Coder for any reason, call NWS-Green Bay (1-800-788-6883 ext. 468) with your report. Tell them your ID first

• (LKSW3). • • If possible, reports should be sent in Weather Coder no later than 830 am (anytime

between 5 am and 830 am).

• Go to the proper sections to report frost depth penetration and depth of frost thawed. See the ? buttons for assistance.

                                                                                                                                                                                          

 

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About your observation...

Location:Oconomowoc South, WI (ONCW3)

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Precipitation

Precipitation:

x.xx in

    

Snowfall:x.x

in

    

Snow depth:

x in

    

Snow core:

x.x

in

    

Dew & Frost Data

Depth of frost penetration:

x in

    

Remarks for form B-91

              limited to 40 characters

      

Frost depth data posted to HYDMKX product - RiverPro

• BELOW IS INFORMATION ABOUT WISCONSIN FROST DEPTHS AS MEASURED BY VOLUNTEERS WITH NWS FROST DEPTH GAGES. FROST DEPTH MEASUREMENTS ARE REQUESTED A MINIMUM OF TWICE WEEKLY-MONDAY MORNINGS AND THURSDAY MORNINGS NOVEMBER THROUGH APRIL. DATA ALIGNED APPROXIMATELY FROM NORTH TO SOUTH. THIS IS AN EXPERIMENTAL PROGRAM. DATA NOT AVAILABLE FROM ALL AREAS OF THE STATE. COMMENTS ARE WELCOME. CONTACT BRIAN.HAHN@NOAA.GOV

• • FROST TIME/DATE OF TODAY'S• DEPTH LAST FROST SNOW DEPTH • ID COUNTY LOCATION (IN.) DEPTH REPORT (IN.)• PRQW3 VILAS PRESQUE ISLE 0 08 AM MON NOV 08 0• LOKW3 VILAS LAND O LAKES-10 W 0 08 AM MON NOV 08 0• LKSW3 VILAS LAND O LAKES-4 W 0 07 AM MON NOV 08 0• LGKW3 FLORENCE LONG LAKE-3 NE 0 05 AM MON NOV 08 0• ARRW3 FLORENCE AURORA-4 W 0 09 AM SUN NOV 07 M• MOLW3 FOREST MOLE LAKE 0 08 AM MON NOV 08 0

Once a year maintenance to frost depth gages

• - Remove any moisture that may have collected in the outer tube – sponge on the end of a stick

• - Possibly replace colored water in clear plastic tube – handle can be disassembled

• - General cleaning

• Joint project with Wis. Dept. of Transportation at 5 sites

• - Started in Aug. 2004 with the purpose of possibly establishing a correlation between frost depth under snow-free pavement and frost depth under snow-covered grass.

• DOT wants to know frost depth under pavement for “Frozen Road Declaration”. When there are 18” or more of frost under state roads, trucks can temporarily carry heavier loads.

• - NWS frost depth gauge installed at 5 Wis. Highway Maintenance Garages along with a DOT frost depth gauge. DOT gauges are built by a DOT employee in Madison, WI.

• - DOT personnel make measurements from both gauges on a regular schedule. They send reports from the NWS gauge to NWS through WXCODER – same as COOP observers do.

• - Possible expansion of joint network in 2005 and beyond

Wis DOT soil auger machine

Wis. DOT soil auger machine

Wis. DOT soil auger

NWS Frost depth gauge at DOT site

DOT soil auger boring a hole in pavement

Installing DOT frost depth gage in 7 foot hole in pavement

The End