What is a snow squall, anyway?

RAPID CITY, S.D.- Phones chimed with an emergency alert from the National Weather Service this morning.

The notification read: “Snow Squall Morning until 9:00 AM MST. Slow down or delay travel! Be ready for a sudden drop to near zero visibility and icy roads in heavy sn0w.”

So, what even is a snow squall, and why is is so dangerous?

A snow squall is a thin but intense band of snowfall. When wind speeds are high and a string of moisture builds up, blizzard-like conditions can be rapidly dragged through an area in less than an hour.

That’s what makes snow squalls so dangerous. Skies appear calm and clear, and roads are then quickly covered in snow and ice while visibility is reduced to just a few feet. If you’re already on the road and a squall moves in, slick spots can build in a matter of minutes.

Although they’re short lived, they can cause accidents, because travelers are caught off guard and often unprepared. Friday in Rapid City, skies were clear around 8 a.m., and by 8:45, near white out conditions had swept in. Cell phone alerts were pushed out in hopes of warning drivers for the possibility of brief but very hazardous conditions on their morning commute.

It’s best to delay travel until after the squall is over, and if you’re already on the road when the snow moves in, officials advise to exercise caution and safely exit the road until the band has moved through the area.