Last Sunday we walked into what seemed an otherworldly scene.
Long ago, a railroad line was put in across Lake Champlain. Apparently the lake was rather shallow here, because instead of a bridge, a long causeway was installed, with huge chunks of marble. The railway has since been discontinued and the rails ripped out, but the causeway is maintained as a biking and walking path.
Normally the causeway crosses a lot of open water. It is a popular place to look for birds or get away from the summer heat. At the moment though the scene is very different. The lake was frozen as far as we could see – what appeared at first to be wind-blown open water was jagged sheets of ice.
The wind whipped at a predictably steady and cold clip. A warm ‘storm’ had come through, bringing a bit of rain and wet snow and a brief thaw, but the thaw had ended. Temperatures were quickly dropping below freezing with light sleety snow. The wind seemed strong because it was cold, but really it was nothing unusual for this place… the trees in their twisted shapes show that much stronger winds are not uncommon here.
From what I could tell, the lake was frozen all the way across.
I later learned that there was still some open water around the Charlotte ferry. I asked the National Weather Service Burlington office’s facebook page about this, and they told me that some of the lake was still open and the Charlotte ferry still operating… but that they had gotten a satellite photo today that showed that most of the open water had a thin layer of ice (you can see it if you look closely).
(photo from NOAA)
The forecast calls for a snowstorm tomorrow, and then more cold weather, with another snowstorm possible on Sunday. While wind from these storms may break up the ice some, it seems likely that with more cold weather in the forecast, the lake will freeze over completely. When this happens, they say the lake has ‘closed’.
Looking here you can see records of when the lake has closed that go back a long ways. You’ll quickly notice that it used to be quite unusual for the lake NOT to close. Only the mildest of winters saw open water on the lake. Lately, the lake has closed only rarely, with the most recent being 2007 with a relatively late closing of March 2. The ice cover must not have lasted long.
People like to attribute a lot of things to the warming climate. Weird thaws, blizzards, Hurricane Irene, thunderstorms, heat waves, arctic vortexes, you name it. While human-caused climate change has certainly had effects on those weather events, it’s extremely difficult to say how much, and in what way. But a lake as big as Lake Champlain has a memory. Water stores a tremendous amount of memory. Whether the lake closes does not just depend on how cold one winter is – and this one has been a pretty cold one, at least by recent standards. The lake’s temperature is influenced by the previous summer, and the winter before that, and probably even the summer before that. Maybe it goes back a decade. The more the average temperature rises, even if it is just a couple of degrees, the harder it is for the lake to freeze in winter.
So there you have it. The fact that this is the first chance I had since I came to Vermont to walk out on that causeway and see only ice… (it came close a few years ago, but apparently did not close completely)… the fact that it’s even worthy of note… is some of the strongest evidence of a warming climate I’ve ever seen.
And, scaling this upward, the Arctic sea ice also acts in a similar way. Taking that a step further, the amount of sea ice versus open water has effects on the jet stream, including, possibly, making the weather more severe, and contributing to that big list of weather issues above. The system is massively entangled, and confusing, but this time the slow wisdom of the lake shows us all we need to know.
Who knows when the lake will close again after this year. Perhaps changes in the jet stream will make it more common again for a while. Perhaps, ironically enough, the lack of sea ice in the Arctic will drive the jet stream further south and give us a bunch of harsh winters. But maybe, just maybe, I won’t ever see it again in my lifetime. Either of the two is pretty scary if you think about it.