Powerful storm could send temperatures as much as 40 degrees below average and bury several states in snow.
The cold is expected to eventually blanket the central U.S. from the Rockies to the Great Lakes region.
Winter is still a month away
By Monday afternoon, parts of Montana, North Dakota, Minnesota, Michigan and Wisconsin had been buried beneath 8, 12, 14, even 16 inches of snow.
Up to 2 feet of snow is expected in parts of Michigan’s Upper Peninsula by the time the storm ends.
Some farmers in Minnesota and South Dakota were worried that the deep snow would delay harvesting of their corn crops.