March 5-6, 2013 Snowstorm Summary

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Aubrie Doyle
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1 March 5-6, 2013 Snowstorm Summary A powerful and complex late system winter storm system crossed the southern Appalachians from the northwest late on March 5th and then headed northeast off the mid-atlantic Coast during the day on March 6th. Partly due to an atypical forecast track, the tricky timing between most significant precipitation and arrival of deeper cold air, as well as late season mild low level air, especially during daytime hours, made this a challenging forecast for many parts of the area. Confidence was high that there would be significant snowfall (8-12 inches or more) across northern portions of the Blacksburg NWS forecast area, with even higher amounts likely farther north into northern Virginia. However, closer to the track of the secondary surface low, and in lower elevations of the Piedmont, forecasting final snow accumulation amounts was much harder. Snowfall began in some of the higher elevations during the evening of March 5th, but also in the Roanoke Valley and points northward overnight, while many areas southwest of Roanoke, even at higher elevations remained mostly rain or rain/snow mix during the heavier precipitation overnight and could not accumulate much. By the time colder air moved in behind the newly developing low pressure across northeast NC and southeast VA, lingering precipitation bands were confined to far northern and northeastern portions of our area. Colder air was delayed somewhat longer than expected due to the primary low over the Ohio Valley being slow to lose it's influence of advecting warmer air to the east of it, while the secondary low mentioned earlier was trying to pull this cold air in from the northwest. It was not until early on the morning of the 6th before this happened. You can see the evolution of these competing low pressure centers in the animated satellite and surface pressure composite map below (Fig 1). When all was said and done, there were indeed very significant accumulations of heavy, wet snow across northern portions of the area, including 10" in Clifton Forge and Lexington, 12-17" in Bath County, 12" in extreme northern Rockbridge County and even Buckingham County as well. 6-8" were common in parts of Greenbrier Co WV. These areas experienced widespread power outages due to the heavy snow on limbs and power lines (see photos below), which were also exasperated by wind gusts of mph in some places.

2 However many areas also saw large differences across small distances, dependent in part by elevation but also from heavier bands of snow developing in northwesterly flow through much of the day on the 6th. Some Virginia Piedmont locations saw snow falling most of the day, but because of warming daytime temperatures and warm ground conditions, the snow struggled to add up to much. Locations north of our area, especially along the Blue Ridge, picked up 20" or more. For more details on the final tallies, see the snowfall map and text summary below.

3 Figure 1. Infra-red satellite and surface analysis evolution, showing the complex double structure to the low pressure system, and the primary low moving over the Ohio Valley and only slowly dissipating, while eventually the secondary low takes over to the east to finally bring colder air in behind it, and then slows down temporarily (keeping snow bands across much of northern VA), before finally shifting out eastward off the coast. Notice also the deeper clouds (with heavier precipitation) move through much of NC and SW VA fairly early (by late evening on the 5th), leaving very little left of the precipitation in those areas by the time the cold air arrived.

Here is a radar loop showing the initial precipitation wave pushing through, followed by wrap-around bands across northern VA (snow by this time) that pivot in place mainly just to the north of our

4 Here is a radar loop showing the initial precipitation wave pushing through, followed by wrap-around bands across northern VA (snow by this time) that pivot in place mainly just to the north of our area resulting in the heaviest accumulations across far northwestern VA. Forecasts of snowfall leading up to the event were better in some places than in others, with confidence the highest across the northern parts of VA, and less confidence farther south and east where it was expected to be a close call between how much precipitation would be left when cold air arrived, and how warm the ground would be. Below is a NWS snowfall forecast provided on a national scale, which local offices adjust as needed, which was issued during the day on the 5th.

5 Figure 2. Preliminary snowfall forecasts from the NWS Weather Prediction Center, issued midday on March 5th. These photos, courtesy of Michele Fletcher in Rockbridge County, show the damage caused by heavy wet snow, with power lines downed by trees, and a power pole, with transformer lying in the ditch.

7 The final snowfall accumulation map for the counties covered by the Blacksburg NWS office is shown below.

8 List of final snowfall reports received at the NWS Blacksburg office: PUBLIC INFORMATION STATEMENT SPOTTER REPORTS NATIONAL WEATHER SERVICE BLACKSBURG VA 1239 PM EST THU MAR THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN DURING THE PAST 48

9 HOURS FOR THE STORM THAT AFFECTED OUR REGION. APPRECIATION IS EXTENDED TO THOSE WHO PROVIDED REPORTS. THIS SUMMARY IS ALSO AVAILABLE ON OUR HOME PAGE AT WEATHER.GOV/BLACKSBURG. ********************STORM TOTAL SNOWFALL******************** LOCATION STORM TOTAL TIME/DATE COMMENTS SNOWFALL OF /INCHES/ MEASUREMENT NORTH CAROLINA...ASHE COUNTY... 3 SW CRESTON AM 3/07 COCORAHS 6 NW LANSING AM 3/07 COCORAHS WEST JEFFERSON AM 3/06 VIA FACEBOOK 1 NE WEST JEFFERSON AM 3/06 COCORAHS TROUT AM 3/06 PUBLIC...WATAUGA COUNTY... 1 SE BEECH MOUNTAIN AM 3/07 COCORAHS BEECH MOUNTAIN AM 3/06 LAW ENFORCEMENT BLOWING ROCK AM 3/06 TRAINED SPOTTER BOONE AM 3/07 CO-OP OBSERVER 1 SSE VALLE CRUCIS AM 3/06 COCORAHS VALLE CRUCIS AM 3/06 TRAINED SPOTTER 5 ESE BANNER ELK AM 3/06 COCORAHS 1 N BOONE AM 3/06 COCORAHS SUGAR GROVE AM 3/06 FIRE DEPT/RESCUE VIRGINIA...ALLEGHANY COUNTY... CLIFTON FORGE CITY AM 3/06 LAW ENFORCEMENT RICH PATCH AM 3/06 VIA TWITTER 1 W NATURAL WELL AM 3/06 CO-OP OBSERVER 4 E COVINGTON AM 3/07 COCORAHS 4 E COVINGTON CITY AM 3/06 2 IN THE PAST 2 HOURS POTTS CREEK PM 3/05 LAW ENFORCEMENT CALLAGHAN PM 3/05 LAW ENFORCEMENT

10 ...AMHERST COUNTY... 4 NW NAOLA PM 3/06 TRAINED SPOTTER 4 N PLEASANT VIEW PM 3/06 TRAINED SPOTTER AMHERST AM 3/ CALL CENTER 1 NNE BUFFALO HILL AM 3/06 PUBLIC 5 W FORKS OF BUFFALO AM 3/07 CO-OP OBSERVER PLEASANT VIEW PM 3/05 TRAINED SPOTTER 1 N GIDSVILLE AM 3/06 TRAINED SPOTTER MADISON HEIGHTS AM 3/06 TRAINED SPOTTER 1 W SANDIDGES AM 3/06 PUBLIC...APPOMATTOX COUNTY... 2 S STONEWALL AM 3/06 VIA FACEBOOK 2 S APPOMATTOX AM 3/07 CO-OP OBSERVER APPOMATTOX AM 3/06 PUBLIC...BATH COUNTY... BOLAR WARM SPRINGS HOT SPRINGS PM 3/ CALL CENTER PM 3/ CALL CENTER PM 3/ CALL CENTER...BEDFORD COUNTY... PEAKS OF OTTER SUMMI AM 3/06 BROADCAST MEDIA 3 WNW BIG ISLAND AM 3/07 COCORAHS 4 NW BEDFORD CITY AM 3/06 CO-OP OBSERVER 1 NE POWELLS STORE AM 3/06 PUBLIC 5 NW LYNCHBURG AIRPO AM 3/06 WSET VIA TWITTER 1 N BEDFORD AM 3/06 COCORAHS 4 SW HUDDLESTON AM 3/06 CO-OP OBSERVER...BOTETOURT COUNTY... 2 N DALEVILLE PM 3/06 PUBLIC FINCASTLE AM 3/06 LAW ENFORCEMENT 5 W FINCASTLE PM 3/06 PUBLIC 2 NNW FINCASTLE AM 3/06 COCORAHS BUCHANAN AM 3/06 CO-OP OBSERVER 4 WNW TROUTVILLE AM 3/06 COCORAHS LAYMANTOWN AM 3/06 VIA FACEBOOK...BUCKINGHAM COUNTY... 2 NNE BENT CREEK PM 3/06 TRAINED SPOTTER GOLD HILL AM 3/06 TRAINED SPOTTER

11 3 NE ANDERSONVILLE AM 3/07 CO-OP OBSERVER 3 SW NEW CANTON AM 3/06 EMERGENCY MNGR BUCKINGHAM AM 3/06 LAW ENFORCEMENT...CAMPBELL COUNTY... ALTAVISTA AM 3/06 LAW ENFORCEMENT CONCORD AM 3/06 PUBLIC LYNCHBURG AIRPORT AM 3/07 ASOS 6 SSW LYNCHBURG AM 3/06 COCORAHS 1 S GLADYS AM 3/07 COCORAHS 2 E LYNCHBURG AIRPOR AM 3/06 COUNTY OFFICIAL 3 E BROOKNEAL AM 3/06 COCORAHS...CHARLOTTE COUNTY... PHENIX AM 3/06 PUBLIC 1 W CHARLOTTE COURT AM 3/07 CO-OP OBSERVER...CITY OF BEDFORD... BEDFORD CITY AM 3/06 LAW ENFORCEMENT...CITY OF BUENA VISTA... BUENA VISTA CITY AM 3/07 CO-OP OBSERVER...CITY OF COVINGTON... COVINGTON AM 3/06 PUBLIC...CITY OF LEXINGTON... 1 ESE LEXINGTON CITY AM 3/07 CO-OP OBSERVER...CITY OF LYNCHBURG... 2 NW LYNCHBURG AIRPO AM 3/06 WSET...VIA TWITTER. 1 WSW LYNCHBURG CITY AM 3/06 BROADCAST MEDIA LYNCHBURG CITY AM 3/06 BROADCAST MEDIA LYNCHBURG AM 3/06 EMERGENCY MNGR...CITY OF ROANOKE... ROANOKE AM 3/ FT ELEVATION 1 ESE ROANOKE AIRPOR AM 3/07 ASOS...CITY OF SALEM... SALEM CITY AM 3/06 DEPT OF HIGHWAYS

12 ...CRAIG COUNTY... SIMMONSVILLE AM 3/06 TRAINED SPOTTER PAINT BANK AM 3/06 FISH HATCHERY NEW CASTLE AM 3/06 3 INCHES POTTS MTN...FLOYD COUNTY... 6 S COPPER HILL AM 3/06 COCORAHS COPPER HILL AM 3/06 CO-OP OBSERVER 5 N FLOYD AM 3/06 VIA TWITTER...FRANKLIN COUNTY... 4 W ROCKY MOUNT AM 3/06 COCORAHS...GRAYSON COUNTY... TROUT DALE AM 3/07 CO-OP OBSERVER 3 SSW ELK CREEK PM 3/06 TRAINED SPOTTER...MONTGOMERY COUNTY... 4 N BLACKSBURG AM 3/06 VIA FACEBOOK 5 NNE BLACKSBURG AM 3/06 NWS EMPLOYEE CHRISTIANSBURG AM 3/06 SOCIAL MEDIA...ROANOKE COUNTY... CAVE SPRING AM 3/06 PUBLIC 2 W CAVE SPRING PM 3/05 PUBLIC 1 NNW HOLLINS AM 3/06 CO-OP OBSERVER 5 NE ROANOKE AM 3/06 PUBLIC 3 N BOONES MILL AM 3/06 COCORAHS 6 SW ROANOKE AM 3/06 COCORAHS 5 SW ROANOKE AM 3/06 COCORAHS 4 SW ROANOKE AM 3/06 COCORAHS...ROCKBRIDGE COUNTY... 3 NNE ROCKBRIDGE BAT PM 3/06 TRAINED SPOTTER 3 NNW VESUVIUS AM 3/ IN RAPHINE 7 NNE BUENA VISTA CI AM 3/06 NEAR MT PLEASANT 3 SW ROCKBRIDGE BATH PM 3/06 TRAINED SPOTTER 2 WNW LEXINGTON CITY AM 3/06 PUBLIC 1 SE GLASGOW AM 3/07 CO-OP OBSERVER COLLIERSTOWN AM 3/06 SOCIAL MEDIA

13 ROCKBRIDGE BATHS PM 3/05 TRAINED SPOTTER NATURAL BRIDGE PM 3/05 EMERGENCY MNGR...SMYTH COUNTY... 2 N MARION PM 3/06 TRAINED SPOTTER 4 WSW MARION AM 3/06 COCORAHS 2 ENE MARION AM 3/06 COCORAHS WEST VIRGINIA...GREENBRIER COUNTY... QUINWOOD PM 3/06 DEPT OF HIGHWAYS CRAWLEY AM 3/06 EMERGENCY MNGR RENICK AM 3/06 EMERGENCY MNGR ALTA AM 3/06 DEPT OF HIGHWAYS SMOOT PM 3/06 TRAINED SPOTTER RUPERT AM 3/06 DEPT OF HIGHWAYS RONCEVERTE AM 3/06 DEPT OF HIGHWAYS AUTO AM 3/06 NO POWER LEWISBURG AM 3/06 DEPT OF HIGHWAYS KESSLER AM 3/06 PUBLIC MCROSS AM 3/07 CO-OP OBSERVER 4 SE RONCEVERTE AM 3/06 COCORAHS CALDWELL AM 3/06 EMERGENCY MNGR DROOP MOUNTAIN PM 3/05 DEPT OF HIGHWAYS FAIRLEA AM 3/06 EMERGENCY MNGR WHITE SULPHUR SPRING AM 3/06 EMERGENCY MNGR CLINTONVILLE PM 3/05 EMERGENCY MNGR ALDERSON AM 3/06 CO-OP OBSERVER CHARMCO PM 3/05 PUBLIC...MERCER COUNTY... FLAT TOP AM 3/06 DEPT OF HIGHWAYS BLUEFIELD AM 3/06 DEPT OF HIGHWAYS PRINCETON AM 3/06 DEPT OF HIGHWAYS 1 NE MERCER CO AIRPO AM 3/07 ASOS 1 SSE BLUEFIELD AM 3/06 VIA FACEBOOK...MONROE COUNTY... GLACE AM 3/06 COUNTY OFFICIAL GAP MILLS AM 3/06 COUNTY OFFICIAL 2 N WAITEVILLE AM 3/06 DEPT OF HIGHWAYS

14 SWEET SPRINGS AM 3/06 DEPT OF HIGHWAYS PICKAWAY AM 3/06 COUNTY OFFICIAL UNION AM 3/06 COUNTY OFFICIAL...SUMMERS COUNTY... 1 NNW HIX AM 3/06 DEPT OF HIGHWAYS 3 N CLAYTON AM 3/06 DEPT OF HIGHWAYS PIPESTEM AM 3/06 DEPT OF HIGHWAYS FOREST HILL AM 3/06 DEPT OF HIGHWAYS HINTON AM 3/06 DEPT OF HIGHWAYS Local Climate Water & Weather Topics: Current Hazards Current Conditions Radar Satellite Climate Weather Safety Contact Us National Weather Service Weather Forecast Office Blacksburg 1750 Forecast Drive Blacksburg, VA (540) Questions or Comments? Send us Last modified: March 26, 2013

STORM TOTAL SNOWFALL

********************STORM TOTAL SNOWFALL******************** PUBLIC INFORMATION STATEMENT SPOTTER REPORTS NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1005 PM EST WED MAR 06 2013 THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN DURING THE PAST 12 HOURS FOR