"map of unusual and extreme winter weather in the U.S.Click for larger: Map of recent unusual and extreme weather events in the U.S.Image: National Wildlife Fund

Starting tonight, Monday, Jan. 31, a winter storm of “historic” proportions will affect up to 100 million Americans, “from the Front Range of the Colorado Rockies to the Ohio Valley to the coast of New England,” says the Weather Channel.

Blame Canada climate change: Cold air blowing down from Canada is the proximate cause of Tuesday’s and Wednesday’s remarkably cold temperatures. But the epic levels of snow and ice coming our way are just the sort of thing we can expect more of as the planet warms, says a report from the National Wildlife Federation.

Chicago-izing the whole country: First it was the “Midwest accent” that spread to all the nation’s newscasters. Now we all get to experience the singular clobbering powers of “lake effect” snow.

Cold temperatures aren’t enough to cause inclement winter weather — that’s why Antarctica is technically the world’s largest desert. In fact, because cold air is automatically drier, it takes the meeting of cold temperatures with masses of warmer, moister air to bring the pain, snow-wise. This has long happened with warm air above the Great Lakes, but thanks to climate change, we’re basically all lakes now. Warmer winter temperatures and more moisture are already leading to more precipitation, as well as shifting storm tracks northward, says the NWF.

Extreme weather kills:

The National Weather Service has issued an unusually dire blizzard watch, calling a storm expected to arrive Tuesday afternoon over much of northern Illinois and Northwest Indiana “dangerous, multifaceted and potentially life-threatening.”

(Chicago Tribune)