What Is A Snow Squall? The Science Behind An Unsuspecting Driver’s Worst Nightmare

Winter is just around the corner, and that means snowfall.

However, not all snowfalls are created equally. Today, we are discussing snow squalls.

Snow squalls are an unsuspecting danger for travelers, able to turn driving conditions from good to treacherous in an instant and sometimes resulting in multi-vehicle pileups, as seen in the photo below.

Got your attention? Good. Let's break it down.

Snow Squalls And Their Criteria

Let's start with the definition. They are brief, but intense, bursts of snowfall that can suddenly drop visibility and slicken roads. Because of its rapid movement, accumulations from a snow squall can be light, but it's not all about snowfall totals.

The drop in visibility can create whiteout conditions in minutes, which you can see below.

Snow Squall Warnings

These heavy bands of snowfall are so notorious that the National Weather Service (NWS) issues snow squall warnings for the danger.

They are short-duration and specify a localized area similar to what you would see with a tornado warning. You can see an example of a warning below that was issued for a snow squall south of downtown Chicago in December 2024.

These are no different from other NWS warnings in that they are targeted at state and local officials, media, the general public and more. You should also get a Wireless Emergency Alert on your smartphone.

A Sudden Onset

Now, say you are driving in good winter conditions, with the pavement dry, but you notice a white haze far ahead.

You don't see a winter storm warning in effect, so you plow forward (pun slightly intended). If you are expecting just a few flurries, get ready to be proven wrong. Within just a few minutes, it all changes. The snow squall arrives.

Strong winds howl, and a combination of blowing snow and falling snow creates a whiteout. Visibility plummets, and you can barely see outside your car. On top of this, you feel the traction of your tires slipping as you try to drive forward.

As soon as you brace for impact, the snow squall moves on and conditions clear up. Sometimes blue skies can even appear. Crazy, right?

Pressing play below or going to this link gives an idea of what it's like to drive into these blinding walls of snow.

Filling A Gap

Some snow squalls can occur without a large-scale winter storm ongoing.

To clarify, this means that they often accompany weather systems that aren't expected to produce snowfall totals high enough to trigger NWS winter weather alerts that cover broad parts of one or more states.

"There are a few rare winter events each year that don't fit the mold of a winter storm warning or winter weather advisory and was determined to be a gap in our services," said Tim Halbach, warning coordination meteorologist at the National Weather Service near Milwaukee, in an email to weather.com in 2019.

Snow squall warnings fill that gap to show that these conditions still need to be taken seriously.

How To Stay Safe

Here are some practical steps you can take this winter when it comes to snow squalls:

-First off, the next time you hear "snow squall" mentioned by a meteorologist in your area, take the threat seriously.

-Delay your trip until the snow squall passes. Put simply, there is no safe place on the road in a snow squall.

-If you must travel, turn on your headlights, slow down, leave more distance between you and the vehicle in front of you and avoid slamming on your brakes, which could lead to a loss of control on a slippery road.

-If you become stopped on the road or involved in an accident, do not stand along or near the road, as approaching vehicles may not be able to see you and may have lost control of their vehicles.

Rob Shackelford is a meteorologist and climate scientist at weather.com. He received his undergraduate and master’s degrees from the University of Georgia studying meteorology and experimenting with alternative hurricane forecasting tools.