Winter Weather Terms
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Last Updated: Sep 27, 2024, 03:01 PM
Watches, Warnings and Advisories
- Winter Storm Watch - Indicates severe winter weather such as heavy snow or ice is possible within the next day or two. Prepare now!
- Winter Storm Warning - Indicates heavy snow (4”+ in southern IL, 6” + northern or central IL), heavy sleet (½” +), or a combination of winter weather hazards are highly likely or occurring. Stay indoors and adjust travel plans!
- Ice Storm Warning - Heavy accumulations of ice will create extremely dangerous travel, damage trees and likely cause extended power outages.
- Blizzard Warning - Strong winds of 35 mph or greater will combine to produce blinding snow, near zero visibility, deep drifts, and life threatening conditions – especially for those that attempt travel.
- Wind Chill Warning - Life threatening wind chills of 25 to 30 below zero or colder.
- Winter Weather Advisory - Indicates snow (2-4” in southern IL, 3-5” in northern or central IL) or a combination of winter weather conditions will cause significant inconveniences and may be hazardous, especially to motorists. Use caution if you venture out!
- Freezing Rain Advisory - Light accumulations of ice will cause hazardous travel.
- Wind Chill Advisory - Dangerous wind chills of 15 to 24 below zero.
Winter Weather Definitions
- Freezing Rain - Rain that freezes when it hits a surface; creating a coating of ice on roads, walkways, trees and power lines.
- Sleet - Rain that turns to ice pellets before reaching the ground. Sleet also causes moisture on roads to freeze and become slick.
- Wind Chill - A measure of how cold people feel due to the combined effect of wind and cold temperatures; the Wind Chill Index is based on the rate of heat loss from exposed skin. Both cold temperatures and wind remove heat from the body; as the wind speed increases during cold conditions, a body loses heat more quickly. Eventually, the internal body temperature also falls and hypothermia can develop. Animals also feel the effects of wind chill, but inanimate objects, such as vehicles and buildings, do not. They will only cool to the actual air temperature, although much faster during windy conditions.