Colorado Winter Weather Terminology and Information Sources

While yesterday we focused on travel tips/safety under Colorado's Winter Weather Awareness Week, today we shift focus to winter weather advisories, watches, warnings and all the other terminology that accompanies the notice that winter conditions are either on the way or ongoing.  Today, we will cover both the terminology and also how to gain access to it using Colorado-specific points for information.

Winter weather conditions arguably have the most fascinating and colorful language of all the weather periods.  Starting with horrifically-sounding "thunder snow" (thunderstorm where precipitation is snow rather than rain) to the equally attention-grabbing "snow eater" (term used to describe warm, dry wind that melts snow) or even "freezing drizzle" (describes condition where small water droplets freeze upon contact with a surface), winter weather is abound with great terms.  Incidentally, our other non-winter weather terminology favorites that could also double as rock band names?  Hail Core.  Fire Tornado.  Wall Cloud. 

The most important words, of course, according to our friends at the National Weather Service, are:
  • Winter Storm WATCH - A winter storm watch is issued when winter storm conditions are possible within the next 3 days but the timing, intensity or occurence may still be uncertain.
  • Winter Storm WARNING - Heavy snow is occurring or will develop in the next 36 hours.  This snow may be accompanied by winds greater than 15 mph and blowing snow.
  • Blizzard WATCH - A blizzard watch is issued when blizzard conditions are possible in the next 12 to 36 hours.
  • Blizzard WARNING - Blizzard warnings are issued in lower elevations when heavy snow is expected to last 3 or more hours with sustained winds of 35 mph or greater and when there is considerable falling and or drifting snow that reduces visibility to less than 1/4 mile.  In the mountains, a blizzard warning is also accompanied by an expectation that winds will exceed 50 mph at higher elevations.
  • Wind Chill WATCH - A wind chill watch is issued in advance of a wind chill warning, usually 12 to 36 hours in advance of the expectation that a warning will be issued.
  • Wind Chill WARNING -  The wind chill warning is issued for wind chills of least -25 degrees on the plains and -35 degrees in the mountains or foothills.
  • Freeze WATCH - Similar to the wind chill watch, a freeze watch is issued in advance of an anticipated freeze warning, usually 12 to 36 hours in advance of when the freeze warning will be issued.
  • Freeze WARNING -  Freeze warnings are issued during growing seasons when temperatures are expected to drop below 32 degrees.
  • High Wind WATCH -  When high wind conditions are expected to develop in the next 12 to 36 hours, a high wind watch is issued.
  • High Wind WARNING - Sustained winds of 50 mph for at least 1 hour or gusts up to 75 mph for any duration in the mountains or foothills will trigger a high wind warning.  In lower elevations, the criteria is somewhat less, set at sustained winds of 40 mph for at least 1 hour or gusts up to 58 mph for any duration.
  • Winter Weather Advisory - A winter weather advisory is the "heads up" that general snow accumulations between 4 and 8 inches over a 12 hour period in the mountains and 3 to 6 inches over a 12 hour period in lower elevations, are expected.  In addition, if visibility is expected to diminish as falling and blowing snow make it difficult to see or if wind blown snow is anticipated to create a visibility hazard for travelers, a winter weather advisory may be issued.  Even freezing drizzle and other conditions involving snow and sleet that primarily impact driving conditions may trigger a winter weather advisory.
  • Dense Fog Advisory - Dense fog advisories are issues when fog will reduce visibility to less than a quarter mile.
  • Wind Chill Advisory - In the mountains, a wind chill advisory will be issued when values are in the -25 degree range and on the plains, a wind chill advisory will be issued when values are between -18 and -25 degrees.
  • Frost Advisory - Unique to the growing season, a frost advisory is issued when temps are expected to drop to between 32 and 35 degrees on clear, calm nights.
There are a number of ways in Colorado to keep up with the advisories, watches and warnings.   As with all emergency public information and warnings, the best practice is to monitor a number of different information points.  So, where can you go in Colorado for advisories, watches and warnings?
And for the best information regarding your own emergency kits for your home/car, for tips on creating a family communications plan and much, much more, keep up with READYColorado at http://readycolorado.com
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