We are in the midst of Snow Squall Awareness Week within Pennsylvania.

A hotbed for these heavy, short-duration wintry bands, this week is a reminder for those in the Keystone State to know how to prepare and react.

While snow squalls may not be too familiar for everyone, especially over the state line in Ohio, these bands are the wintry version of thunderstorm squall lines we are accustomed to.

Snow squalls form from low-pressure systems that move through our area. Cold fronts moving toward the region lift up vast amounts of cold air, mixing the atmosphere to a point where the air gets quite unstable. As a result, the air condenses into tall, towering clouds, which are also strong enough to produce precipitation.

 

 

Because the lift from the front can be so strong, these squalls can pack a snow-filled punch. However, snow squalls lack a sustainable duration, meaning those in the path get slammed with heavy snowfall, albeit between a third and a full hour from start to finish. 

Just like summertime thunderstorms, snow squalls can be a bit of a surprise as clouds quickly roll in. Snowfall can accumulate between 1” and 5” an hour, and also cause significant snow drifts with heavy wind. The combination of heavy snowfall and strong winds tanks visibility down to near-zero, known as whiteout conditions. By far, snow squalls are worse for those travelling on the roads, thanks to this.

 

 

Folks driving into a snow squall typically experience a whirlwind of weather leading up to it. As these squalls are small, it’s not uncommon for skies to stay sunny five to ten minutes before snow arrives. By the time the car is driven into the squall, drivers’ fields of view drop dramatically, making it hard to see the car in front. In addition to visibility concerns, snow begins to accumulate on the road, making fast driving or quick stops extremely unsafe. Squalls are one of the leading causes of large, multi-vehicle pileups on the highway, one of the many ways folks succumb to Mother Nature.

 

 

It is for this reason that the National Weather Service created Snow Squall Warnings in 2018. In order to issue these warnings, heavy snow must reduce visibility to less than one-quarter mile, along with wind gusts above 34 mph and rapidly falling temperatures, resulting in a high likelihood of a flash freeze. Since then, Pennsylvania and New York have led the nation in warnings issued per year, at around 42. Other states along the East Coast, such as Massachusetts, New Hampshire, Vermont, and New Jersey, also regularly issue multiple warnings each year. It becomes uncommon along the Great Lakes. Ohio has only issued four warnings a year since 2018, while Indiana and Kentucky don’t typically issue more than one a year. 

 

 

The “bullseye” of snow squall activity, for that reason, is largely centered within New York and Pennsylvania. While cities just off the Great Lakes, such as Buffalo and Erie, as well as major Northeast cities such as New York, Philadelphia, and Boston, are not hotbeds, major Interstate Highways can be routinely affected. Drivers on I-80, I-76, I-81, and I-79 within Pennsylvania (to name just a few) must take extra precautions during the winter months in case of squalls.

 

 

The best way to deal with a squall is to know it’s coming- always check the weather forecast before driving, especially during the wintertime. If snow squalls are forecasted, delay your travels until you know the risk of squalls has subsided. In doing this, whiteout conditions on major roads can be avoided. If you are travelling when a snow squall hits, try to leave the road or highway as soon as possible. If this is not an option, slow down significantly and travel with your hazards on to signal to others on the road.

 

 

Even slow driving may not be enough to avoid a multi-car pileup on the highway. If this occurs, do the best you can to get yourself out of harm’s way. The back of the pileup- or the place you just entered- is the most unsafe part of a pileup, as cars may fly unknowingly into the pile. If safe to do so, exit the car and get as far away from the roadway as possible. If this is not an option, try to get as far forward in the pileup as you can.

Download the Storm Tracker 21 app for snow-squall-related winter weather updates.