It’s polar vortex day across much of the United States. Temperatures are plunging well below zero, close to the point where going metric doesn’t change a thing. It’s a day to stay inside and huddle, a day to not only be glad you’re still alive but wonder why you live where the air hurts your face.
It is not, however, a day to talk about climate change. These things just happen on a big continent with interesting geography. The same forces that water it and keep it green also create nasty weather patterns that can kill us all. It’s a big part of the North American experience, and it’s why people tend to migrate freely in this part of the world and have since humans first arrived.
So let’s talk about the Jet Stream again, and why this is just one of those things.
First of all, we should start with the high level maps of the situation. The Jet Stream is the normal west to east flow at higher latitudes. It’s caused by the drag flow of our rotating planet not being as strong once you move away from the equator. A constant 20 knot trade wind from the east as we slip through the atmosphere, not quite dragging it all with the spinning ball, loops back around where the spin is lower halfway to the pole.
That’s a quick take on it. The short answer is that there’s a lot of wind from the west under normal circumstances once you go north enough.
That doesn’t mean it’s constant, however. The spine of the Rocky Mountains is tall enough to mess things up a bit, and a strong low pressure over the middle of North American can suck air from Alaska and the arctic down along the leeward side of the mountains from time to time. Conditions have to be just right for it to happen, but it does this several times a year in the winter.
Every few years there is a very strong “Alberta Clipper” that brings the North Pole down to us.
This doesn’t happen, at least not to the same degree, in Asia. The Jet Stream can develop kinks which work their way around the planet it a cycle of roughly ten days. But they are simply not as strong over Siberia because the geography allows for a straight flow. It all tends to
straighten out over Russia.
This is a perfectly natural phenomenon that has been recorded for hundreds of years. It may be getting worse due to climate change and the presence of more low pressure over the continent which sets up the effect. But we can’t tell simply by looking at the weather one way or the other.
It’s important to simply enjoy the small disaster the best you can. That means staying inside and helping out those who need it in a spirit of being all in this together. It’s the way of northern people, who have enough trouble in life just dealing with weather. Getting along and getting by just makes life better when the air hurts your face.
Is this a sign that we’re all doomed? Truth be told, no one lives forever. This continent is much older than any of us. People have dealt with this for centuries, primarily by huddling together through the winter and moving on when they had to in the Spring. It’s what we do. And we all pass on at some point for the next generation to take over and do their own thing, wherever that takes them.
In short, this is the kind of weather that makes North America what it is. We’re a tough people who move on when we have to. This is not a day to keep moving, however, it’s a day to just get by and get along.
And for those of you not in the middle of this I hope you can understand. It’s Minnesota. We talk about the weather a lot because it’s far more interesting than it should be.