Winter Storm Categories
Wyoming weather can change at any time. It can be something simple as just light snowfall, or a treacherous blizzard. Knowing the terms can help you to take the necessary precautionary measures.
Severe/Hazardous Weather Terms:
Winter Storm Outlook –
Issued prior to an official Winter Storm Watch issuance. The outlook is given when forecasters believe winter storm conditions are possible. This prediction is usually issued 3-5 days in advance of the winter storm.
Winter Storm Watch –
Alerts the public to the potential for blizzard conditions, heavy snow, significant icing, or combination of these events. Watches are usually issued 12 to 48 hours before the beginning of the winter storm.
Winter Storm Warning –
Issued when a combination of heavy snow, heavy freezing rain or heavy sleet is expected to occur. Winter storm warnings usually are issued when hazardous weather is occurring or imminent.
Heavy snow – Six inches or more of snow in 12 hours or less or eight inches or more in 24 hours.
Significant icing – Usually an ice accumulation of ¼ inch or more from freezing rain, an accumulation of ½ inch or more of sleet, or a combination of freezing rain and sleet.
Ice Storm Warning – Heavy ice accumulations will cause extremely dangerous and damaging situations, such as icy roads and downed power lines.
Blizzard Warning – Issued for sustained or gusty winds of 35 mph or more and falling or blowing snow creating visibility below ¼ mile. The conditions should persist for at least three hours.
Wind Chill Advisory - Issued when wind chills are expected to be -34 degrees Fahrenheit or lower. However, an advisory may be issued for wind chills from -20 to -35 degrees Fahrenheit early or late in the winter season.
Wind Chill Warning – Issued when wind chills are below -30 degrees Fahrenheit
Winter Weather Advisories – Issued for winter weather conditions which will cause significant inconvenience and may be hazardous. If you are cautious, these situations should not be threatening.
- For snow – Three to five inches of snow is expected
- For freezing rain, freezing drizzle – Any accretion or accumulation up to ¼ inch
- For blowing and drifting snow – when blowing snow will restrict visibility to 1/8 mile or less and cause significant drifting snow
Dense Fog Advisory – Issued when widespread fog will reduce visibility to ¼ mile or below and persist for two hours or more.
High Wind Warning – Issued when sustained winds of 40 mph or greater are expected to last one hour or longer or wind gust of 60 mph or greater.