Winter Storms: Watch, Warning and Advisory Criteria
Types of Message
The National Weather Service issues WATCHES, WARNINGS, and ADVISORIES to alert the public to potentially dangerous winter weather events or situations.
A WINTER STORM WATCH means that severe winter conditions, such as heavy snow and/or ice, may affect your area, but its occurrence, location and timing are still uncertain. A winter storm watch is issued to provide 12 to 36 hours notice of the possibility of severe winter weather. A winter storm watch is intended to provide enough lead time so those who need to set plans in motion can do so.
A WINTER STORM WARNING is issued when 4 or more inches of snow or sleet is expected in the next 12 hours, or 6 or more inches in 24 hours, or 1/4 inch or more of ice accretion is expected.
A WINTER WEATHER ADVISORY informs you that winter weather conditions are expected to cause significant inconveniences that may be hazardous.
If caution is exercised, these situations should not be life threatening.
Means that snow and strong winds will combine to produce a blinding snow (near zero visibility), deep drifts, and life-threatening wind chill.
- Issued for winter storms with sustained or frequent winds of 35 mph or higher with considerable falling and/or blowing snow that frequently reduces visibility to 1/4 of a mile or less. These conditions are expected to prevail for a minimum of 3 hours.
The NWS does not issue watches or warnings for storms that produce less than 4 inches of snowfall, but these storms can be deceptively dangerous. The majority of deaths linked to snow storms are as a result of traffic accidents, and many of those accidents occur with only small accumulations of snow. Slow down as soon as snow begins to accumulate.