Saturday, November 22, 2014

Buffalo's Ongoing Disaster......

A plea for help in snowbound Hamburg, N.Y.
Photo by Mark Mulville,  Buffalo News.  
I know I've been harping on the epic lake effect snows near Buffalo, N.Y., but I can't help myself. This is one of the most amazing and strange weather events I've ever seen.

It's not over, either. Next up: The possibility of epic flooding. Yeah, 60 degree temperatures, high humidity and rain falling on seven feet of snow would do that. And it's in the forecast.

The amount of snow that fell continues to astound me and a zillion other people.  The big "winner," if you will is the town of Cowlesville, N.Y. which got 88 inches of snow over four days. Yep.  That's more than seven feet of snow and enough to bury an NBA player.

Close behind were West Seneca with 78 inches and Hamburg with 79 inches. That's about the normal snowfall for an entire winter, basically November to April, where I live in northwestern Vermont. And those towns got it in four days.

Now, as I said, it's looking increasingly likely the snow disaster near Buffalo will get worse. Rain, high humidity and very warm temperatures will conspire to melt the snow rapidly, leading to a potentially nasty flood. 

Under normal conditions, the next storm system coming through is pretty normal for November. Often, a strong, windy storm will howl northward across the Great Lakes, hauling a slug of warm, rainy weather through the Buffalo region with it.
The weight of the snow was too much for this building
in Hamburg, N.Y. Photo by Brian Connolly, Buffalo News.  

It pretty much happens every November.

But until now, it's always happened when there wasn't seven feet of snow, with a water content of four to six inches, sitting on the landscape, just waiting to melt and cause a bad flood.

At first, any rain that falls will soak into the snow. (Although it doesn't help matters that some areas will have to contend with some freezing rain today in the snow zone. Ugh.)

But as the snow continues to melt, the big snow banks will act as dams, holding water back from its normal drainage routes. That means that even houses that aren't right near flooding creeks and rivers could be in trouble.

If a house or other building is on the wrong side of one of these snow dams, it could flood.

Plus the storm drains are all buried under heaps of snow, so the water can't go there. Plus the leaves came off the trees just prior and during the storm, so the storm drains could be further clogged with leaves.

Even if a particular building doesn't get into the flood waters, there still could be trouble.
According to The Vane, the weather blog at Gawker:

"The biggest story we'll hear out of this snowmelt might not be the flooding, but rather the structural damage that comes from water-logged slush pressing up against the walls and sitting on roofs. We will see roof collapses from this event.

Box stores are notorious for suffering from structural failures when rain falls on a dense snow pack, but the amount of snow on residential roofs will also pose structural problems." 

It's already nasty out there. The Buffalo News said 13 people have already died from the storms, and at least 30 structures have collapsed from the weight of the snow.

I'm reluctant to blame every extreme weather event on global warming, and it does seem counter intuitive to blame a massive snowstorm on global warming, but Eric Holthaus, writing in Slate, makes a very plausible case for the hand of climate change in this disaster.

Lake Erie was warmer than usual, thanks to a mild autumn. The lake temperature has been going up gradually as the yearly average temperature rises in tandem.

Lake effect snows thrive on the contrast between warm lake water and the cold air above it. The warmer the water and the colder the air, the more intense the lake effect snow is.

The cold wave that helped spawn the extreme lake effect was stronger than you'd expect for mid-November. Record low temperatures were set all around the eastern United States.

As Holthaus writes, the jet stream has gotten a lot wavier in recent years and decades, and it has included sharper kinks southward at times, causing more intense cold waves to occur, interrupting the generally warmer conditions we've seen.

The jet stream connection to global warming, especially the fact that the jet stream has gotten more erratic, is still under study, but it's worth looking at.

So if global warming makes the lakes warmer, and makes a few of the cold spells, goes the logic, then lake effect snows can get stronger because of global warming.

I'm not sure Holthaus is right. It's hard to connect global warming to any single weather event. But like I said, his argument is plausible.

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