PHOTO: Major Flight Delays at Airport

NEW YORK, N.Y. - Winter-like weather is hitting the Midwest and Northeast portions of the United States hard, affecting holiday travel for over 56 million Americans.

Some roads in the Midwest are completely impassable and a plane in Buffalo, New York slid off the runway while taxiing, and got stuck in the grass.

Flight delays are wide-spread across the country, affecting nearly every major airline. Over 420 flights were cancelled Sunday, according to flight tracking website Flight Aware.

Delta Airlines released a statement on Saturday announcing that 22 of its Northeast destinations and 16 of its Upper-Midwest stops were likely to be affected by winter delays.

American Airlines issued a travel alert for more than 40 North American airports in the Dakotas all the way to Michigan and throughout the Northeast.

The alert even extended to some international hubs, like John F. Kennedy International Airport and the Philadelphia International Airport. The airlines estimates over 2.7 million of its customers could be impacted through Tuesday.

The National Weather Service's Sunday forecast calls for heavy snow for the upper Mississippi Valley, the upper Great Lakes and in parts of the Northeast, freezing rain in the parts of the Mid-Atlantic and southern New England, showers and thunderstorms in the Tennessee and Mississippi valleys and rains in some parts of Southern California and the Pacific Northwest.

Ice storm warnings are in effect from western Maryland to central Pennsylvania, where the National Weather Service is expected "severe travel disruptions."

In Spokane, one arriving United Airlines flight from San Francisco, California was cancelled. Two flights to Phoenix, Arizona have been cancelled, as well as one flight to Denver, Colorado, according to the Spokane International Airport's flight tracker.

Its unclear if any of the delayed flights are weather related.