Disaster Resources - University of Illinois Extension

Weather Terms

The National Weather Service uses the terms below to convey the weather threat to the public. It is important that everyone understands these terms and knows what actions need to be taken at that time.

Wind Chill: A calculation of how cold it feels outside when the effects of temperature and wind speed are combined. A strong wind combination with a temperature of just below freezing can have the same effect as a still air temperature about 35º colder.

Freezing Rain: Rain that freezes when it hits the ground, creating a coating of ice on roads and walkways.

Sleet: Rain that turns to ice pellets before reaching the ground. Sleet bounces when hitting a surface and does not stick to objects. An accumulation of sleet can make roads slick and hazardous.

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 severe winter weather conditions are occurring, imminent, or highly likely. Stay indoors!

  • Heavy Snow Warning : Snowfall of six inches or more.
  • Ice Storm Warning : Heavy accumulations of ice will create extremely dangerous travel and damage trees and power lines.
  • Blizzard Warning : Snow and strong winds will combine to produce blinding snow, near zero visibility, deep drifts, and life threatening wind chill.

Winter Weather Advisory : Indicates winter weather conditions will cause significant inconveniences and may be hazardous...especially to motorists. Use caution!

  • Snow Advisory : Snowfall of three to five inches.
  • Wind Chill Advisory : Dangerous wind chills of 35 below zero or colder.
  • Freezing Rain/Sleet Advisory : Light accumulations of ice will cause hazardous travel.
  • Blowing/Drifting Snow Advisory : Poor visibility and hazardous driving conditions.

Remember these terms because the next time you hear them, your life and the lives of others may depend upon it!!

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