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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Weathercatch: Snow squalls? Watch out if you encounter one

By Nic Loyd and Linda Weiford For The Spokesman-Review

On Valentine’s Day morning, Mother Nature surprised drivers heading to work in Bozeman with a blast of snow and wind that abruptly transformed relatively clear skies into blizzard conditions.

Then, in less than an hour, the sky turned blue again.

A snow squall had blown through. And though these flash winter storms are commonly associated with the Great Lakes region, they sometimes strike here in the Pacific Northwest – like the menacing one that descended over a freeway in Spokane last Nov. 26.

Around 2 p.m. that day, a wind-whipped band of snow engulfed a 10-mile stretch of Interstate 90 just west of the city, triggering a massive number of vehicle accidents. Near-whiteout conditions and slick pavement resulted in pileups involving more than 60 cars. Fortunately, no one was critically injured.

What’s remarkable is how fast this snowstorm swooped in, that it covered such a localized area and lasted only 30 minutes. Photographs taken an hour after the storm moved in show dozens of vehicles pitched in every direction along the snow-glazed freeway, with benign patches of blue sky above.

It was a classic snow squall – “an intense, short-lived burst of heavy snowfall that leads to a quick reduction in visibility and is often accompanied by intense winds,” as defined by the National Weather Service.

Unlike blizzards, which last for hours and even days, snow squalls usually last 30 to 60 minutes. Up to an inch of snow falls during that time, which may not seem like much, but when combined with strong winds and suddenly reduced visibility, wintertime squalls can have deadly consequences.

Which is why the weather service has added snow squalls to its list of warnings, right along with tornadoes and flash floods. Several weeks after the weather event in Spokane, technology made it possible for people to receive snow warnings on their smartphones via Wireless Emergency Alerts.

But don’t expect your mobile phone to buzz a snow squall warning well in advance, as you would with a blizzard. Snow squalls typically develop quickly and in small geographic areas, making it more challenging for forecasters to predict. The event along I-90 occurred during a day when radar and available data indicated no snow was expected in Spokane. The weather began changing only about an hour before the squall started to erupt.

“If a snow squall warning is issued for your area, your best bet is to avoid or delay motor travel until the squall passes through your location,” the National Oceanic and Atmospheric Administration advises on its website. If you’re already on the road, make sure your lights are on and slow down, it adds.

With March only a week away, could we experience another snow squall during the 2019-20 winter season? Possibly, if the air near ground level becomes warmer than the cool air aloft, combined with other conditions. In the meantime, know that location-specific alerts on our smartphones can warn us just in time. For more information on these Wireless Emergency Alerts go to: weather.gov/wrn/wea.

Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: ldweiford@gmail.com.