Winter Weather Causes More than 1,200 Flight Cancellations at Chicago O'Hare

Twenty states are under winter weather alerts.

— -- A blanket of snow and a blast of frigid air is causing travel troubles from the Midwest to the Northeast.

Today, airports across the country have racked up nearly 3,000 delays and 600 cancellations.

Up to a foot of snow fell in Minnesota, while Chicago saw about 8 inches and about 10 inches covered Detroit, according to ABC News Meteorologist Max Golembo.

New York City's Central Park got its first measurable snow accumulation of the season, with a dusting of just .4 inches.

Snow and wintry precipitation made for messy, difficult traveling conditions on Monday morning in the Northeast as commuters made their way into work. Boston saw 1 to 2 inches overnight and snow continued to fall into the early morning.

Below freezing temperatures are expected for millions across a large part of the country in the coming days as an arctic blast moves in from Canada.