christmas, as tonight, millions of americans are getting a head start on the holiday but hitting an obstacle course of weather. In many parts of this country. Reports coming in tonight of accidents,... See More
christmas, as tonight, millions of americans are getting a head start on the holiday but hitting an obstacle course of weather. In many parts of this country. Reports coming in tonight of accidents, cars overturned on the highway. Roads covered with snow and ice. And at the airports, a lot of families waiting online, bags in hand. Flights already cancelled. Abc's meteorologist ginger zee is tracking the tricky effort to get home for the holidays. Reporter: Bustling, tussling, beginning to look like it could be a holiday travel nightmare. Snow in seattle, washington. And an icy mix that had drivers spinning out and crashing. I saw a red pickup hit a green van and then he went to the left and then I ended up t boning him. Reporter: In topeka, cars up ended and rear ended. In rockford, illinois, a 20 car pileup, road crews sweeping up the mess with brooms. And in grand rapids, michigan freezing rain, glazing roads making it nearly impossible to drive. And watch this pup lucy really struggling to walk. Amidst the blinding snow in saint cloud, minnesota, clouds fighting to keep up. The fire department fighting this blaze in temperatures near zero. In green bay, working overtime, shoveling to keep lambeau field clear for sunday's game. For the more than 40 million taking to the air this holiday season, tonight is the busiest night. More than 200,000 expected just at chicago's o'hare today. Including this woman, who i think is the happiest traveller in the world. Were you concerned at all. No. As long as you get here early. I'm the one. Reporter: South of chicago the threat turns to damaging winds and isolated tornadoes. Parts of arkansas, mississippi, louisiana and tennessee are all in that elevated risk. I spent a lot of time in chicago, lived here five years, o'hare looking really good tonight. But this is going to change tomorrow, let me show you why. Ahead of that, and north of that severe weather, you can see flooding from texas up to western new york, and then that snow and ice, chicago itself right there in the wintry mix, and north of it, up to ten inches of snow, back into parts of even northern missouri and eastern iowa. And tomorrow, diane, we officially begin winter. If you can believe it or not. I can believe it. Thank you, ginger, for reporting in tonight.
This transcript has been automatically generated and may not be 100% accurate.