Two powerful winter storms blanketed huge swaths of the central United States Monday and threatened to bury much of the northern portion of the country in the coming days.
"It's a pretty good sized mass of storms," said Pat Slattery of the National Weather Service. "It's going to be around for a while."
The first storm was creating blizzard conditions in parts of Montana and North Dakota and was expected to pound parts of the central plains and upper midwest before hitting the Appalachians Tuesday.
A second storm was forming in the Rocky Mountains and was expected to reach the central plains by Monday evening, at which point it would join up with the first storm in a huge mass of biting wind and blowing snow.
The weather service warned that travel would be hazardous or even impossible at the height of the storm, which is expected to reach the heavily populated Chicago area just in time for the morning rush hour on Tuesday and will linger long past the evening rush.
"Accumulation rates of one to 1.5 inches (2.5 to 3.8 centimeters) per hour are possible at times making snow removal difficult and travel extremely dangerous," the Chicago office of the weather service warned.
Up to 10 inches (25 centimeters) of snow were expected in the Windy City by the time the storm passes on Tuesday night.
Wind gusts of up to 50 miles per hour (80 kilometers) were creating huge drifts and whipping up the snow into near-white out conditions in North Dakota and Montana Monday where as much as 15 inches (38 centimeters) of snow was expected.
"Roadways will become drifted shut from blowing and drifting snow," the weather service's Montana office warned.
"If trapped in the blizzard do not leave your car. Disorientation can occur quickly in low temperatures and white out conditions which can lead to a life threatening situation."
The weather service also warned farmers that "newborn livestock will need to be protected against the elements today."