Snow Squalls Create A Dangerous But Beautiful Saturday In Vermont/Northeast

A snow squall west of St. Albans, Vermont early Saturday
afternoon. You can see the towering clouds with the
squall and if you look close, intense snow falling from
the base of these clouds. This squall produced
whiteout conditions in many areas of northwestern
Vermont, focusing on Highgate and Swanton.

 Saturday was a really interesting weather day in Vermont and most of the rest of the Northeast as a well-forecasted batch of snow squalls roared through the region.  

Pretty much everyone was affected by the squalls from Michigan to Maine and from Quebec to Pennsylvania.  Social media was full of snow squall time lapse videos showing dark clouds approaching, then visibility going from perfect to zero in an instant, then recovering back to normal just as fast. 

A video from the John Hancock tower, and my ground view video of the St. Albans evening snow squalls are at the bottom of this post 

True to form, Saturday's squalls didn't last long in any one location.  Most places only had intense snow for just a few minutes. The heavy snow was so brief in Burlington, Vermont that they only measured 0.3 inches of new snow and a trace of melted precipitation. 

Other places got a little more snow if they were repeated bullseyed by squalls. I got about an inch of wind-blown snow in St. Albans. Several towns reported two to four inches. High elevation Readsboro in far southern Vermont received six inches. 

Obviously, with the sudden zero visibility, the squalls can be dangerous.  Saturday morning, a period of heavy snow and intense blowing snow on the Route 2 Causeway in South Hero caused zero visibility and a series of crashes, forcing a temporary closure of the wind-exposed section of highway. Six people were injured in the crashes, reports WCAX.

Smart phones throughout the Northeast including mine in St. Albans, Vermont buzzed and blared all day with emergency alerts warning of the snow squalls.

The warnings, much like severe thunderstorm warnings, cover an area of just a few counties at a time and tell people to stay off the roads until the snow squall passes.  And that visibility issue is real. 

Fascinating visible satellite image from about 12:30 p.m.
Saturday. Click on the image to make it bigger and 
easier to see. The bright cloud line from northern New
York just west of Lake Champlain all the way down to northern
Maryland is the main snow squall line. A line of snow squalls
is also coming off Lake Ontario. New snow squalls are 
forming in northern New York and in Quebec southwest of 
Montreal, and those would come through 
Vermont in the evening. 

 I was on the road less than a half mile from my house heading home when an evening snow squall abruptly blew in.  I couldn't see my mailbox from 50 feet away as I prepared to turn into my driveway.  Luckily, I was safely back home for the bulk of the snow squall. 

The widespread snow squalls were created by a compact, vigorous "Alberta Clipper" type storm coming in from the west from the Great Lakes into far southern Ontario and Quebec with an equally vigorous cold front dangling southward from the storm center. 

A pocket of cold air aloft led to a big temperature change from the surface to several thousand feet up in the air. This helped lead to the towering clouds that produced the snow squalls.

I also think there was a hint of a sign of spring in these squalls. That sound counterintuitive, but hear me out.

The sun angle is increasing fast now from its December lows. That means the sun is starting to more effectively heat the ground.  The sun yesterday did just that, adding more updrafts to feed the snow squalls and make them stronger. That's the same process that is often necessary for strong summer thunderstorms. 

It doesn't look like we have more snow squalls in the immediate forecast. However, you'll want to be careful out in open areas of the Champlain Valley today, especially near that notorious Causeway in South Hero. Strong south winds are forecast this afternoon, and that will blow the snow around quite a bit, causing some more visibility problems in spot.

Videos:

As always, click on the hyperlinks in the text if you don't see an image of the video. If you see the video, click on the red arrow then the YouTube logo.

First video is snow squalls skirting close by my place in St. Albans in the afternoon, then a snow squall scores a direct hit on St. Albans in the evening: 

Next video is from CBS Boston. It's a time lapse camera view from atop the John Hancock building as a snow squall sweeps through Boston Saturday evening.