Winter Weather in North Dakota

Winter Weather Safety

The National  Weather Service Issued A What?

The National Weather Service issues a variety of watches, warnings and  advisories during times of severe winter weather. Keep the following weather words in mind this winter season:

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Watch
Watches are issued when the risk of a hazardous winter weather event has increased, but its occurrence, location, and/or timing is still uncertain. Watches are usually issued a day or two before the event. Watches may be dropped, or upgraded to advisories or warnings.

img7.gif (1636 bytes) Warnings and Advisories
Are issued when a hazardous winter weather event is occurring, is imminent, or has a high probability of occurrence. A Warning is used when there is a threat to life or property. Advisories are for less serious conditions that cause inconvenience, and, if caution is not used, could lead to situations that may threaten life or property.
img8.gif (1726 bytes) Blizzard
By definition a blizzard is a storm with winds of 35 mph or higher AND visibility frequently below ¼ mile in snow and/or blowing snow AND these conditions last for three (3) hours or longer. There is no set temperature requirement for a blizzard.
 


Wind Chill

Wind chill is the apparent temperature or "what it feels like" when the effects of temperature and wind speed are combined. Advisories are issued for Wind Chill values of 25 to 39 degrees below zero when the wind is 5 mph or more. Warnings are issued for Wind Chill values of 40 below zero and colder when the wind is 5 mph or more. These conditions would have to persist for more than an hour and over a larger geographical area (at least several counties) for an advisory or warning to be issued.

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Warning and Advisory Type
Winter Storm Warnings are issued for combination events, like snow mixed with sleet or freezing rain, or combined with wind and blowing snow. Generally, the criteria for a Winter Storm Warning is six inches of snow in 12 hours or less, or, eight inches of snow in 24 hours or less. When significant and damaging freezing rain is expected (a quarter inch or more of ice accumulation), an Ice Storm Warning would be issued. Blizzard Warnings are issued when the definition of a Blizzard (above) is expected to be met. Wind Chill Warnings and Advisories are issued when the definition (above) is expected to be met. Winter Weather Advisories are issued for combination events (snow with freezing rain or sleet, or snow with wind and blowing snow) when warning criteria is not expected to be met. Generally, Winter Weather Advisories are issued for 3-5 inches of snow. Freezing Rain Advisories are issued when mainly freezing rain (less than a quarter inch of ice accumulation) is forecast but warning criteria is not expected to be met.

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