Snow squalls can happen at a moment's notice and pose extreme danger to motorists who are unfortunate enough to drive into this sudden burst of heavy snow.
Imagine needing your sunglasses one minute, but then you drive into a white wall of wind-driven snow the next minute and can barely see the car in front of you. That's what it's like to be caught in a snow squall on the highway.
Think of a snow squall like a miniature blizzard with gusty winds that typically lasts less than an hour. Very high snowfall rates, on the order of 2 inches in 30 minutes, are not uncommon.
"Snow squalls are often what cause these large multi-vehicle pileups in the winter," said John Banghoff, a meteorologist at the National Weather Service office in State College, Pennsylvania. "It's very disorienting. We've seen some videos of this phenomenon where you can just be driving along and go from blue skies to whiteout conditions in a matter of seconds, and before you realize it, you're racing down the road unable to stop, unable to really control your vehicle."
As roads quickly become snow-covered, it's especially difficult for vehicles to come to a stop during a snow squall. Visibility can drop to one-quarter mile or less, so you might not see another vehicle in front of you until it's too late.
- Image 1 of 4
- Image 2 of 4
- Image 3 of 4
- Image 4 of 4
"We often see that commercial trucks such as semis are some of the biggest vehicles that take the longest to stop, and as a result, you can have passenger vehicles that have zero chance whatsoever," Banghoff said. "In fact, a lot of the deaths occur because of the combination of all the pileups that occur in these really unfortunate events."
There is no safe place on a highway during a snow squall, the NWS says. That's because even if you pull off onto the shoulder, vehicles can still hit you if other drivers lose control and slide off the road.
The NWS issues Snow Squall Warnings to encourage motorists to delay travel until the snow squall has passed, or for those already on the road, to exit the highway at the first possible opportunity so that you're not on the road during these extremely dangerous winter driving conditions.
A Snow Squall Warning will trigger a Wireless Emergency Alert on your smartphone, similar to a Tornado or Flash Flood Warning.
If you have no choice but to continue driving through a snow squall, Banghoff said there are four things you can do to increase your odds of staying safe.
"We recommend avoiding slamming on your breaks, turning on your headlights and hazard lights, staying in your lane and increasing your following distance," said Banghoff. "The hazard lights are perhaps the most important thing so that people can have an idea that there are other vehicles there."