So, in case anybody didn’t know, Boston is sitting under about six feet of snow right now. Six feet.
Just to put that in perspective, if you had a ground-level door in Boston, with no porch or overhang above it, and you opened that door, you wouldn’t see the outside. Mostly, you would see a wall of snow. Unless your indoor lights were on, most of the wall would appear black, because even a few inches of snow completely block light. The very top of the cliff would look blue or white, and you’d be able to see the sky through a six-inch gap between the snow and the top of the door. And all of it has fallen in the past thirty days.
More heavy snow is on the way this weekend.
Predictably, certain people are yammering that so much snow disproves global warming, while others point out, correctly, that climate change actually causes more snow. I agree that global warming = more snow does sound counter-intuitive, but we all know that climate change is complex, bringing floods to some places and droughts to others, etc. Perhaps snowy Boston is similar? But no. Actually, the thing with snow is not complex at all.
Here’s the deal; when the air is below freezing, precipitation falls as snow. That means that until a given area warms so much that it no longer freezes in winter, it will continue to get snow. If a big, wet, storm moves in during freezing weather, it will get a lot of snow. A giant blizzard (or several of them in a row) is what a flood looks like in New England in February.
And indeed, while the Boston area has been colder than average for February this year, it hasn’t been that much colder. It hasn’t dropped to zero (Fahrenheit) this month yet, although one below-zero night is average for February in Boston. The record lows for each day in the first twelve days of February are all below zero–and no cold weather record has been broken in early February in Boston for eighty-one years (in contrast, of the heat records for the first twelve days of this month, six were set over the last twenty-five years).
So, we’re not looking at especially cold weather right now. What we’re looking at is a flood that happens to be frozen.
And for New England, climate change generally takes the form of floods, some of them catastrophic. Temperatures have risen dramatically as well, but most of the change has involved nighttime lows, when most people are asleep. It is the flooding most people notice. The event that we’re seeing now is comparable in scope to Tropical Storm Irene, Superstorm Sandy, and all the other major floods, named and unnamed, that have wet New England in recent years. At least fifteen people have already died (and that figure is six days old), counting those who succumbed to the same storms in other areas. Snow storms typically kill through traffic accidents and heart failure triggered by the effort of shoveling. Very heavy snowfalls, like these, can collapse roofs from the weight. I have not heard of anyone being under a roof when it collapsed, but it must happen. Boston alone has or will spend over twenty million dollars on snow removal and other blizzard-related costs from just the storms of the past month. The snow season still has another month to go.
Where I live, in Maryland, we’ve hardly had any snow all year–just a light dusting a few times and a couple of flurries. We see the New England storms on the news, but the TV coverage usually makes it look like a giant pain in the neck and not much more. And my friends in New England all seem to be fine, if a little tired of the snow, so a mere inconvenience is all it is for many. But, it’s important to realize that it’s more than that for some people, and the regional infrastructure–which was not designed to deal with this much snow–is being severely strained. This is an extreme weather event and it is dangerous.
How does it relate to climate change?
Generally speaking, a warmer atmosphere carries more water and so delivers more floods. When it rains, it pours is the weather-mantra of the new age. But specifically, this series of storms is linked, not so much to warm air, but to warm water.
My friend, the science educator/weather geek explained to me that:
The snowiness is being caused by an upper level and persistent trough of low pressure. There is a strong High pressure ridge over the Western US that is bringing warm weather to the great plains and wet/cold weather to the eastern third of the US. Not sure when it will move away, probably not for another couple weeks.
The reason why this ridge of high pressure causes different kinds of weather in different places is that air rotates around it clockwise. So that rotation is pulling warm air up from Mexico into the Great Plains (and ruining Garrison Keilor’s winter), to the west of the trough, while pulling cold weather down from Canada to the East. Climate change may be making these sorts of things more common or more severe, but it is nonsensical to ask whether a single storm reflects a trend–trends are only visible across time.
In any case, so we’ve got persistently cold, damp weather in the Eastern part of the country periodically bubbling up into storm systems, some of which intensify into nor’easters along the coast. A nor’easter is an extra-tropical cyclonic storm that feeds off of cold air and a warm ocean. They might loosely be considered winter hurricanes (though they can happen in summer, too), because they bring wind and coastal flooding (with snow or rain) in a similar way.
BUT this February, sea temperatures have been abnormally high. As of a few days ago, sea surface temperatures off of Cape Cod (meaning many miles off the coast–in the Gulf Stream and beyond) were twenty-one degrees Fahrenheit above normal for this time of year. That doubled the amount of moisture in the air, dramatically increasing the amount of snow that a system feeding in the region could dump.
Again, it’s hard to say if one pool of warm water is climate change, because climate change is a trend not an event, but we do know the ocean is getting warmer. And when it gets warmer, Boston gets buried under six feet of snow.