Severe Cold And Big Lake Effect Snows Will Probably Prompt Climate Arguments, Again

The six to 10 day forecast into the beginning of January
keeps the eastern United States quite cold. 

We're now in the heart of a long, long Arctic cold wave in much of the eastern two thirds of the nation that will close out 2017 and begin the first several days of 2018.

Wind chill advisories and warnings this morning extended from Montana to Maine and south as far as Kansas.

Locally, here in Vermont, winter chill advisories are up in the "warmer" valleys like the Champlain, and wind chill warnings are up elsewhere. It's too bad it's so cold: Ski conditions for the holiday week in the mountains are actually quite good. Better than most years.

Now that we've got the long, long, cold wave established and we're still getting those lake effect snows, activists who concentrate on climate change are going to be making noise again.

I'll give you the bottom line first, then the explanation:

For those of you who say all this cold and lake effect, deep snows are "proof" that the climate isn't warming, you're wrong.

For those of you way all this persistent cold and record breaking snows are signs of climate change, you're not wrong, exactly, but I think you could be overdoing it.

First of all, I have to give the usual statement before I dive into this whole thing: Individual weather events in small parts of the world are very rarely a clear signal of climate change, though they can be influenced by the phenomenon.

Also, to state the obvious, winter cold waves like this one have always happened with or without climate change. Arctic blasts in the winter are perfectly normal. As are lake effect snowstorms near the Great Lakes.

This is, of course, a very strong cold wave. International Falls, Minnesota had a record low of 36 below this morning, and the town of Cotton, Minnesota made if to 41 below.

As cold waves go, this one is covering a pretty big area, too. It goes most of the way across southern Canada, and covers, or will cover all but the southwestern 25 percent of the United States.

But in the grand scheme of things, even that vast cold area isn't all that big when you take the entire Earth into consideration.

So if it's cold where you are, you are not experiencing the whole world. You're freezing your ass off. That's not global warming. It's just bad luck where you are, if you hate cold weather.

Even though this cold wave will last up to two weeks in some places, that's not climate. It's weather. People always tell us to think of it this way, and it make sense: Climate is nature's personality, weather is her mood. In other words, good natured people are occasionally angry. Weather sometimes very briefly goes against decades long trends. No big deal.

Now, could this weather set up be a perverse symptom of climate change? Well, possibly, but there's a lot of more mundane things at work here, too.

Let's look at that epic, record shattering lake effect snowstorm in Erie, Pennsylvania, the one that dumped 60 inches of snow on the city in two days. Lake effect snows, as I've said, are normal. Cold air sweeps across the relatively warm waters of the lakes, easily picks up moisture and deposits that moisture on the shore as snow.

Lake effect storms usually arrange themselves in narrow bands. In the middle of these snow bands, it's a zero visibility blizzard. Five miles on either side of these bands, the sun might be shining. Often, but not always, these snow bands move north or south, east or west a little bit, depending on the prevailing wind, so no one place stays in the heavy snow.  

Erie, Pennsylvania was buried under 60 inches of snow
in two days. Photo by Greg Wohlford, Erie Times Union

Sometimes the snow bands do stay in one position. And if the wind comes from a direction that is most efficient at picking up moisture from the lake, the result is incredible amounts of snow.

That's what happened in Erie. The band of snow stayed positioned over the city, and the direction of the wind was perfect for manufacturing LOTS of snow.

So that's the main reason why Erie got clobbered. However, there is a legitimate climate change angle to all this. If the overall air temperature in the Great Lakes are warmer, despite the occasional cold snap, the lakes will be warmer, too. Warmer lakes mean more moisture can get into the air, making the lake effect snowstorms that much more intense.

Also, lake effect doesn't work if the lakes are frozen over. The cold winds can't pick up moisture from the lake water if that water is sealed off from the atmosphere by ice. As Climate Central points out, if it's an overall warmer winter, the lakes don't freeze as quickly, and you have more opportunities for lake effect snows on the occasions it does turn cold.

Now what about this extended cold spell? Is climate change influencing it? Well, it's possible, but certainly not definite. Cold waves lasting this long have always occured on occasion, so this isn't some weird unprecedented climate change disaster.

However, there is some scientific evidence that a relative lack of sea ice in the Arctic, as we are experiencing now, can help weather patterns in the mid-latitudes where we live get "stuck" so a particular kind of weather would last longer than it otherwise would.

It's been a very warm winter once again in the Arctic, so ice cover up there is below normal. That means it's within the realm of possibility that this cold wave here is lasting longer than it otherwise would.

I have no idea if that's actually the case right now, and I doubt any scientist yet knows, either. But it's definitely something for people smarter than me to study, to really understand if melting Arctic ice is messing with weather patterns much further south.

Meanwhile, stay nice and bundled up. You're going to be cold for awhile!