KANSAS CITY, Mo. — Happy Thursday, Weather blog readers!
Every week we air a segment called Weather Academy where I give you a quick explainer on different weather phenomena throughout the year.
This week, I wanted to focus on snow squalls as a big winter storm is impacting the Mountain West and the upper Midwest.
Before & after (5 minutes) images of when of the snow squall moved through the Grand Lake area. Near whiteout conditions & snow covered roads are expected with the snow squalls. #cowx— NWS Boulder (@NWSBoulder) February 22, 2023
*images courtesy of Western Riviera Lakeside Lodging pic.twitter.com/WpBQ2H6oso
First, what is a snow squall?
It's essentially a winter version of a squall line of thunderstorms as the physical mechanisms that cause these to form are very similar.
Relatively warmer air rising above relatively cooler air due to a difference in density.
Both types have heavy precipitation, strong winds, and cooler air moving in afterward.
Five states were impacted by snow squalls(purple polygons) on Wednesday: Kansas, Colorado, Nebraska, Utah, and New Mexico.
Notice where the polygons are located, near or along highways and interstates. That's because snow squalls cause a sudden change in visibility and road conditions, resulting in traffic accidents.
SNOW SQUALL INCOMING…— Joe Ruch (@KRDOJoe) February 23, 2023
Check out this photo of todays snow squalls in Huerfano County, CO. Thanks Valrie Eisemann for sharing! #COwx pic.twitter.com/oyZYtHzsyt
Snow squalls also have a unique feature that makes them arguably worse than a thunderstorm squall: the ability to freeze.
Sometimes falling snow from squall lines will melt when hitting the pavement resulting in wet or slushy roads initially. But as the cold Arctic air moves through, a 'flash freeze' occurs causing all the liquid and slush to become ice.
So as drivers go into a snow squall visibility drops, drivers can apply breaks but are unable to stop the vehicle because the road is now ice, resulting in massive pile ups.
UNBELIEVABLE video of a pileup in Schuylkill County as snow squalls brought visibility on Interstate 81 down to near zero. Video shot live by Mike Moye (Facebook) pic.twitter.com/q1BxgUYz2O— Joe Holden (@JoeHoldenCBS3) March 28, 2022
For a local perspective, our National Weather Services offices in Pleasant Hill and Topeka have never issued a snow squall warning, which were first issued in 2019 in effort to reduce those massive pile ups.
These are treated like severe thunderstorm warnings, a line of heavy snow moving through an area lasting 30-60 minutes. Although they brings similar conditions, don't confuse them with a blizzard which can last hours or days.
Alerts for these will be sent to your phone and on electronic billboards telling drivers to stay off the roads until the squall has passed.
It's a good idea now that you ensure your phone's wireless emergency alerts are turned on for incoming spring severe weather.
For more information on Weather Academy or weather updates follow me on all social media platforms @WesWeather.