Winter Weather and Wellness in Vermont

Vermont winter storms come from a handful of happenstance.  The weakest and more localized storms are “mountain-induced events.”  This is weather generated by slope and elevation.  Much of the winter we can earn a bounty through lake-effect snow.  Fronts are what brings most of our meaningful weather.  They are typically driven by two massive and antipathetic wind patterns, prevailing westerlies and polar easterlies.  The largest storms are ‘Nor’easters.’  Most winters (but not all winters) at least an inch of snow falls on at least 20 days and as many as 40 days and the ground is covered by snow from November through at least Easter.  

It's almost too complicated for words.  The winter weather in Vermont is deeply affected by elevation, terrain, slope, which direction a slope faces, wind, localized wind, Lake Champlain, the Atlantic Ocean, ice on the Great Lakes (and Lake Champlain), wind currents in the Pacific (and the Atlantic) to name just a handful of an infinite number of factors.  Needless to say then no two winters are alike.  

As we all know it is hard weather to predict.  Meteorologists describe this difficulty as “highly changeable,” which is a terrific euphemism.

            Take a recent Saturday, for example.  The forecast was for a day of rain and freezing rain.  It was sunny, calm and warm – at least at our house.  It was misty on Mount Mansfield in the morning and rained hard for about twenty minutes.  We never would have know it down in the valley.  I skinned up the mountain late that day under a calm and bright blue sky.  Near the top I experienced high winds (surprise surprise) and thunder.  Thunder in March. 

            Thunder in March is not normal.  Wind is always normal.  Beyond localized conditions, Vermont in winter is affected by the “prevailing westerlies,” which are born in the tropics and driven north.  These winds move the way they do because of the rotation of the earth.  North of us are the “polar easterlies,” which are blocks of extremely cold air driven away from the poles to the west.  The polar easterlies and prevailing westerlies slam into each other around here.  In the winter the boundary is typically southern New England.  In the summer the boundary moves north.

This collision zone is called the “polar front”; warmer moist air to the south, dry cold air to the north.  The collision creates winter storms, typically snow but not always, typically the snow falls here but not always, typically it means Vermont has snow cover from fall through spring (but not always).  The jet stream, racing high above us, determines where this boundary sits day-to-day, year-to-year.  It’s too much to even think about understanding how many variables determine where the jet stream sits.

Forecasters up here must be brave because forecasting is a fool’s errand in Northern New England.  It can make people laugh out loud.  Weather can be decidedly different from one town to another, at one elevation or another, on a north-facing slope compared to an easterly slope.

            The prevailing westerlies can bring us lake-effect snow – moist air brought from open water of the Great Lakes – and the collision between the polar easterlies and westerlies can bring tremendous blizzards.  Occasionally (more and more?) the prevailing westerlies collide so quickly with the polar easterlies that the warm air climbs on top of the cold air creating an inversion.  If the collision causes a storm it can be rain above and turn to ice as it falls through the colder air below.  Ice Storm.  We can also be given the gift of a strong Yankee Clipper, which moves from the colds of the Canadian prairies and races east, typically bringing light snow and then massive cold and sometimes a blizzard.

            Another pattern usually striking late in a winter can hit Vermont hard.  Although the westerlies and the polar easterlies mean we are not a maritime climate, the cold water current along the Atlantic Coast can generate massive storms.  The prevailing westerlies draw warm, moist air from the Gulf of Mexico up the coast.  When the weather hits the cold North Atlantic the pressure becomes cyclonic.  When temperature differences and the size and depth of the collision are strong these colliding patterns generate massive storms – very like hurricanes – driving tremendous amounts of snow (or rain) into Vermont, counter-clockwise from the coast. 

And here’s what we love.  When it’s cold and dry in February and March, a big Nor’easter will bring three feet of snow in a day.  The storms can also reform and cycle through more than once.  A Nor’easter during a cold March can dump as much snow in a day as all of the snow from all of the days of the rest of the winter.  For many it is why we are here.

            We can barely predict the weather.  We have no control over it.  I barely understand it and I am sure there is something metaphoric in writing about it (but like Chance the Gardener I won’t claim to know what it is). 

The only thing certain about the winter weather in our little town is this: nothing we do impacts our collective wellbeing more.  It makes us.  And, to borrow from another film, anyone who tells you differently is trying to sell you something.  In much of the country it is full on spring.  Here, it is too soon for spring.  We crave more winter.

David Rocchio lives, works and writes in Stowe, Vermont. (c) 2011 David Rocchio