What is a snow squall? Sudden storms hit Northeast

Cities across the Northeast were hit by snow squalls Wednesday, as forecasters warned of heavy winds and dangerous road conditions. Multiple warnings for the brief bursts of heavy snowfall were issued throughout the region in states including Pennsylvania, New York, New Jersey, Connecticut and Ohio. 

As of 5 p.m., the only snow squall warning currently in effect was for parts of New Hampshire, according to a map from the National Weather Service. The warning cited “a line of dangerous snow squalls” moving east through the region at 40 miles per hour at 4:25 p.m., and cautioned that “snow may melt on road surfaces and refreeze after sunset.” 

Earlier in the day, snow squalls erupted across a number of northeastern states. Squalls moving through Pennsylvania’s Delaware Valley even brought snowfall heavy enough to obscure Philadelphia’s skyscrapers, according to CBS Philadelphia. 

In Massachusetts, CBS Boston posted a time-lapse video of a squall engulfing the city, appearing to obscure all visibility. 

What is a snow squall? 

According to the National Weather Service, a snow squall is “an intense short-lived burst of heavy snowfall that leads to a quick reduction in visibilities and is often accompanied by gusty winds.” 

Unlike a snowstorm, which can last for many hours or even days, snow squalls occur in quick, intense bursts, the National Weather Service said. A snow squall usually only lasts between 30 and 60 minutes. 

The service warned that snow squalls can bring “sudden whiteout conditions” as well as “slick roadways” that can lead to traffic accidents. 

“Although snow accumulations are typically an inch or less, the added combination of gusty winds, falling temperatures and quick reductions in visibility can cause extremely dangerous conditions for motorists,” the service wrote on its website. “Unfortunately, there is a long history of deadly traffic accidents associated with snow squalls.” 

The weather service cautioned people to avoid driving during squalls, or to reduce their speed if they were already driving when a squall hit.