National Weather Service United States Department of Commerce

 

Winter Weather Preparedness Week for Virginia

November 29 - December 3rd, 2021

 

Please join us in promoting winter weather safety during this year's "Winter Weather Preparedness Week". The National Weather Service asks emergency management, public safety officials, local media and Weather-Ready Nation Ambassadors to help join forces in improving the nation's readiness, responsiveness, and overall resilience against extreme weather during the winter weather season.

 

Each day this week, a different topic will be covered. Click on the tabs below for more winter weather preparedness information.

 

Monday

Winter Season Outlook and winter weather terminology

This will provide you with some terms the National Weather Service uses to describe winter weather as well as the definitions of watches, warnings, and advisories issued for winter weather events.

 

temperature outlook

 

precipitation forecast

 

Watches are issued when a storm is in it's early stage of development, and may create conditions that may harm life and property. Hazardous winter weather is only a possibility, not a certainty. 

The following are the watch headlines issued for winter weather events: 

  • Winter Storm Watch is issued when heavy snow, damaging ice accumulations, or blizzard conditions are possible. Winter Storm Watches are issued across the mountains of Virginia when 6 inches of snow are expected within a 24-hour period, or 5 inches are expected within a 12-hour period. Across the foothills and Piedmont region of Virginia, Winter Storm Watches are issued when 5 inches are expected within a 24-hour period, or 4 inches are expected within a 12-hour period. Likewise, across the entire region, Winter Storm Watches are issued when 2 inches of sleet are expected, and/or 1/4 inch or more of ice accumulation is expected in a 12 to 24 hour period. Winter Storm Watches are also issued for winter events where a mixture of snow, and/or sleet, and/or freezing rain is expected in significant amounts.
  • Wind Chill Watch is issued when dangerously cold wind chills are possible typically in the next 12 to 48 hours. Across the mountains of Virginia, this value is -20° F or colder, and across the foothills and Piedmont, the value is -15° F or colder.

 

Warnings are issued when the threat to life and property is imminent or has already begun from severe winter weather.

The following are the warning headlines issued for winter weather events:

  • Winter Storm Warning is issued when hazardous winter weather in the form of heavy snow, freezing rain, sleet or any combination there of, is imminent or occurring. Winter storm warnings are typically issued 12 to 36 hours before the event is expected to start.
  • Ice Storm Warning is issued when damaging ice accumulations are expected within the next 12 to 36 hours.
  • Blizzard Warning is issued when sustained or gusty winds of 35 mph or more prevail, combined with falling or blowing snow, visibility of one quarter of a mile or less, and last for at least 3 hours.
  • Wind Chill Warning is issued when the combination of extreme cold and winds occur. This combination will result in frostbite, hypothermia, or even death when exposed in this type of condition for an extended period of time. These are issued when wind chill values are expected to reach the values listed within the Wind Chill Watch information.

 

Advisories are issued for less serious weather conditions that will not cause immediate threat to life and property. Advisories will be issued when weather conditions will impact motorists, outdoor activities, or public events. These events could become life-threatening if proper precautions are not taken.

The following are the advisory headlines issued for winter weather events:

  • Winter Weather Advisory is issued for accumulations of snow, lake effect snow, freezing rain, freezing drizzle, or sleet, that will create inconveniences. During an advisory, if caution is not exercised, life and property may be threatened. For an advisory, across the mountains, we would be expecting snow up to 3 inches in 12 hours or 4 inches in 24 hours, and up to 2 inches across the foothills/Piedmont in 12 hours or 3 inches in 24 hours. Any amount of ice accretion warrants an advisory. Light combinations of snow/sleet and freezing rain can also prompt an advisory.
  • Wind Chill Advisory is issued when wind chill temperatures create inconvenience to life with prolonged exposure. If caution is not exercised, hypothermia and frostbite may occur. Issued across the mountains for wind chills values -4° F to -19° F and across the foothills/Piedmont for values of 0° F to -14° F.&

 

Winter infographics

 


 

 

Tuesday

Winter Storms affecting Virginia

The most dangerous winter weather systems for Virginia, which can produce major amounts of snow and ice, are strong coastal low pressure systems known as nor'easters.  These types of storms can impact the region a couple times a season and when the temperatures are cold enough, these types of storms can produce big snowfall events.  For example, On January 22 - 23, 2016, the commonwealth was impacted by a nor'easter with heavy snow with some locations in Northern Virginia seeing up to 4 Feet of snow.  At the same time, strong winds along the coast produced near Blizzard Conditions.  The maps below show just how much snow fell with this storm.

    

 

 

Winter storms can make driving and walking extremely dangerous.  The aftermath of a major winter storm can have a devastating impact for days or even weeks. Winter storms can be deceptive killers because most deaths are indirectly related to the storm.  People die in traffic accidents on icy roads, have heart attacks while shoveling snow, or succumb to fires or carbon monoxide while trying to heat their home improperly.  With proper planning and preparation, you can limit or even mitigate the impacts from winter storms. 

Lastly for today, The National Weather Service needs accurate snowfall measurements during winter storms.  Those accurate snowfall measurements help us to adjust continually update the forecast and warnings during the event.  Are you willing to be a snow observer to help the NWS?  Below is graphic that shows you how to take an accurate snow measurement.  Once you have your report, you can send it to your local NWS office in Blacksburg, VA by:

 

Measuring Snow

 

Winter infographics

 

Wednesday

Excessive Cold and Preparing your home for winter

Cold weather is a fact of winter.  With the cold temperatures comes an increase in the number of house fires.  House fires resulting from heating material within the home ranks second for the most deaths and property loss.  Chimney fires are the number one cause of home heating fires and typically the result of a poorly maintained chimney where creosote is allowed to build up. Space heaters are typically involved in 25 perfect of home heating fires and account for 74 percent of the deaths.  Be sure to test smoke and carbon monoxide detectors and replace any broken detectors and dead batteries. 

 

 

Severe winter storms can produce conditions which can isolate you in your home for several days.  Prolonged loss of power can severely limit your ability to heat your home.  Also obtaining supplies, food and other necessities can be hampered or prevented by poor road conditions.  Make sure to stock an emergency supply of food and water prior to the onset of a winter storm.  Include food items which require no cooking such as canned meats, peanut butter and other non-perishables.  Also do not forget to have necessary medicines and baby items on hand.  A three to five day supply of food and medicine is generally sufficient.  A lot of these items may already be in your home from your hurricane kit. 

Example home emergency supply kit

 

Preparation Kit

 

Winter infographics

 

 


 

 

Thursday

Dangers associated with freezing rain and sleet

Ice falling in the form of freezing rain is particularly dangerous and poses a variety of problems.  The ability of freezing rain to accumulate on nearly every surface, including trees, power lines, and bridges, makes it one of the most dangerous forms of winter weather.  As little as a quarter of an inch of freezing rain can create widespread power outages.  Last winter, central and southern portions of Virginia saw one of the worst ice storms in the last 20 years.  On February 12 - 13, 2021 a long period of light to moderate rain developed and fell into areas with surface temperatures around 30 degrees.  This lead to trees and powerlines being coated in ice and eventually lead to widespread power outages that took nearly two weeks to be fully repaired in some locations

 

    

         Power Outages at peak of storm                        Icing in Crewe, VA                               Icing in Floyd County, VA
               (credit: PowerOutage.us)                     (credit: @wx_Jpeg - Twitter)                           (credit: Jean Martin)

When driving, ice can be very difficult to recognize.  The roadway may appear to be wet when in reality when appears to be water may actually be ice.  If the temperature outside is below freezing, ice can form on the roads, especially on bridges and overpasses.  When encountering ice, do not panic and do not stomp on your brakes.  It is safer to slowly decelerate to a stop. 

 

Winter infographics

 


 

 

 

Friday

Driving in winter weather

Seventy-five percent of all winter weather related deaths occur on the road, either in accidents or by people becoming stranded. When the weather is bad and driving conditions are poor, the best bet is to stay at home

 

  1. Make sure your car is in good running condition. Make sure that your battery, antifreeze, windshield wipers, ignition and thermostat are all in good working order. Be sure your tires have enough tread. Replace any of these items if necessary.
  2. If you must go out when snow and ice are on the ground, let someone know your destination and when you plan to arrive. Also take a cell phone with you if possible. 
  3. Clean snow and ice off all parts of your car before you drive away.
  4. Keep your gas tank as full as possible when snow and ice are forecast. This will not only give you added peace of mind, it also increases the weight of your car and this will provide additional traction.
  5. Keep the following basic items in your car - windshield scraper and brush, booster/jumper cables, a tow chain or rope, bag of sand or salt, blankets, flashlight, first aid kit and road map.
  6. Overall drive slow. Driving at even posted speeds is extremely dangerous when snow and ice are on the road. Many vehicles will lose traction especially at higher speeds resulting in serious accident and vehicle rollovers. 
  7. Steer your car into the skid. If your vehicle loses traction and begins to skid, steer the front tires into the direction of the skid. Never hit your brakes as this will result in a more serious skid and spinning of the vehicle. When your vehicle skids keep your cool and remain calm. Again driving at slower speeds will help you recover from a skid. 

 

 

 

 

Winter infographics

 

 


 

 

Awareness Week Activities

Winter is Coming - Are you Ready? Webinar

December 1, 2021 6:30PM

 

The National Weather Service wants to help you prepare for the winter season. During this presentation you will see the official winter outlook; learn how to find and interpret our winter forecasts; how to be prepared; and how to properly measure and share snow and ice values.

Click here to register.

 

 

Frequently Asked Questions

  1. What have been our extemes for Thanksgiving, Christmas, and New Years Day?

    We invite you to visit Extremes. From this page you can select Temperature, Precipitation, or Snowfall extremes for Blacksburg, VA, Roanoke, VA, Lynchburg, VA, Danville, VA or Bluefield, WV. Then select your desired holiday. You will be presented with a Top 10 list of your search criteria.
     
  2. What is the Winter Storm Severity Index (WSSI)?
     
    The Winter Storm Severity Index, or WSSI, is a new tool from the National Weather Service that forecasts the potential impacts of winter storms throughout the continential United States.

    The WSSI can keep you informed on potential winter storm impacts in your community, including tree damage, property damage, transportation impats, and disruptions to daily life.

    The WSSI is designed to help you prepare before the storm. Expected winter storms are given a color coded "impact rating" in six categories, ranging from "No Impacts" to "Extreme Impacts."

    Click here to view the most recent WSSI maps and to also access additional information about the WSSI product.


     
  3. What is the correct way to measure snow and ice?




     

    You can also send your snow or ice report to NWS Blacksburg using our Storm Report Form!

     

  4. What items should be included in a vehicle Winter Storm Kit?



    Get more information at build your winter storm kit and prepare for cold weather.
     

  5. What is the polar vortex?



    The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles. It ALWAYS exists near the poles, but weakens in summer and strengthens in winter. The term "vortex" refers to the counter-clockwise flow of air that helps keep the colder air near the Poles. Many times during winter in the northern hemisphere, the polar vortex will expand, sending cold air southward with the jet stream (see graphic above). This occurs fairly regularly during wintertime and is often associated with large outbreaks of Arctic air in the United States. 

    Get more information at: Polar Vortex.
     

  6. What is Wind Chill, and how is it calculated?



    Wind Chill is how cold people or animals feel when outside. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. Therefore, the wind makes it FEEL much colder. If the temperature is 0°F and the wind is blowing at 15 mph, the wind chill is -19°F. At this wind chill temperature, exposed skin can freeze in 30 minutes. The wind chill temperature is calculated using the following formula:

    Wind chill (ºF) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)

    Where: T = Air Temperature (F)
    V = Wind Speed (mph)
    ^ = raised to a power (exponential)

    Wind chill Temperature is only defined for temperatures at or below 50°F and wind speeds above 3 mph. Bright sunshine may increase the wind chill temperature by 10°F to 18°F.

    More information on Wind Chill is included at Wind Chill FAQs.

     

  7. What is the difference between frostbite and hypothermia?


     

  8. What is meant by black ice?

  9. Why do bridges and overpasses freeze before other surfaces? 


     

  10. What is a snow squall, and what is the difference between a snow squall and a snow storm?



    The difference between a snow squall and a snowstorm really just comes down to the duration of the event. Snow squalls are usually very short-lived (on the order of 30-60 minutes) and extremely intense. A snow storm could last for several hours or even days. More information is available at Snow Squall FAQ.

 

 

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You can also contact:

Phil Hysell (Phil.Hysell@noaa.gov) for additional information about Virginia's 2021 Winter Weather Awareness Week.

Office