Winter Weather Definitions

The National Weather Service issues many different types of watches and warnings during the winter months. Here is what they mean:
(Courtesy of Skyview Weather - October 2009)

• Winter Weather Watch - A winter storm watch is issued when winter storm conditions are possible within the next 12 to 36 hours, but the timing, intensity, or occurrence may still be uncertain.
• Winter Storm Warning - A winter storm warning is issued when heavy snow is occurring or will develop in the next 18 hours. The heavy snow may be accompanied by wind and blowing snow.
• Blizzard Warning - A blizzard warning is issued when the following conditions are expected for at least 3 hours:
  • Sustained winds of 35mph or greater
  • Considerable falling and/or drifting snow lowering visibilities to less than 1/4 mile.
  Remember, snow does not necessarily need to be falling and dangerous wind chills are often observed during blizzard events.
• Winter Weather Advisory - A winter weather advisory for snow is issued when these general snow accumulations are expected:
  • Between 4 and 8 inches in 12 hours in the mountains.
  • Between 3 and 6 inches in 12 hours at lower elevations, such as Denver Metro.
  • Winter Weather Advisory for Snow and Blowing Snow - A winter weather advisory for snow and blowing snow is issued when falling snow is accompanied by blowing snow to cause travel problems due to lowered visibilities and drifting snow.
  • Winter Weather Advisory for Blowing Snow - A winter weather advisory for blowing snow is issued when wind blown snow will occasionally reduce visibilities and create a hazard for travelers.
• Frost / Freeze warning - Below freezing temperatures are expected and may cause significant damage to plants, crops, or fruit trees in areas unaccustomed to freezing temperatures.  Usually issued for first the frost/freeze of the season and again in the spring for late frosts/freezes.
• High Wind Warning - A high wind warning is issued for the following conditions:
  • Sustained winds of 50mph for at least 1 hour or gusts to 75mph for any duration in the mountains and foothills.
  • Sustained winds of 40mph for at least 1 hour, or gusts to 58mph for any duration at lower elevations away from the foothills.

Weather forecasters use different wording or terms when describing a snow event.  Whether it is just some flurries or a large winter storm forecasters use different words that best suit the snow event that is expected.

• Flurries - Light snow falling for short durations.  No accumulation or just a light dusting is all that is expected.
• Showers - Snow falling at varying intensities for brief periods of time.  Some accumulation is possible.  You can best relate to these by thinking about a summer rain shower, but instead of rain you get snow.
• Squall - Brief, intense snow showers accompanied by strong, gusty winds.  Accumulation may be significant.  Snow squalls are best known in the Great Lakes region.
• blowing Snow - Wind-driven snow that reduces visibility and causes significant drifting.  Blowing snow may be snow that is falling and/or loose snow on the ground picked up by the wind.
• Blizzard - Winds over 35 mph with snow and blowing snow, reducing visibility to near zero.
• Sleet - Rain drops that freeze into ice pellets before reaching the ground.  Sleet usually bounces when hitting a surface and does not stick to objects.  However, it can accumulate like snow and cause a hazard to motorists.
• Freezing Rain - Rain that falls onto a surface with a temperature below freezing.  This causes it to freeze to surfaces, such as trees, cars, and roads, forming a coating or glaze of ice.  Even small accumulations of ice can cause a significant hazard.

Winter Survival Tips

Snow and or severe cold can be potentially life threatening, and every year we see cold and snow related deaths.  Everyone is potentially at risk during winter storms.  The actual threat to you depends on your specific situation.  Recent observations indicate the following:

Related to ice and snow:

• About 70% occur in automobiles.
• About 25% are people caught out in the storm.

Related to exposure to cold:

• 50% are people over 60 years old.
• Over 75% are males.
• About 20% occur in the home.

Definitions:

• Frostbite - Frostbite is damage to body tissue caused by that tissue being frozen.  Warning signs:
   
  • Loss of feeling
  • White or pale appearance in extremities, such as fingers, toes, ear lobes, or the tip of the nose.
  Caring for frostbite:
  • If symptoms are detected, get medical help immediately!
  • If you must wait for help, slowly re-warm affected areas.  Some pain is normal here.
  • If the person is also showing signs of hypothermia, warm the body core before the extremities.
• Hypothermia - Low body temperature.  Warning signs:
  • Uncontrollable shivering
  • Memory loss
  • Disorientation
  • Incoherence
  • Slurred speech
  • Drowsiness
  • Apparent exhaustion
  Detecting and caring for hypothermia:
  1. Take the person's temperature.  If it's below 95^�F (35^�C), immediately seek medical care! 
  2. If medical care is not available:
     1. Get the person out of wet or moist clothing, and wrap them in a warm blanket covering the head and neck.  Dress them in warm dry clothing if possible.
     2. Begin warming the person slowly.
     3. Warm the body core first.  If needed, use your own body heat to help.
     DO NOT:
     • Do not give the person alcohol, drugs, coffee, or any hot beverage or food; warm broth is better.
     • Do not warm extremities (arms and legs) first!  This drives the cold blood toward the heart and can lead to heart failure.
• Wind Chill - The wind chill is based on the rate of heat loss from exposed skin caused by the combined effects of wind and temperature.  As the wind increases, heat is carried away from the body at an accelerated rate, driving down the body temperature.  Animals are also affected by wind chill.

If you are stranded during a Winter Storm...