Transcript for Winter storm bringing dangerous avalanches to Colorado Rockies

Next here tonight, to the relentless winter storms. The new system headed for the northeast. New York, philly, Boston all in the past. Tonight, the extreme avalanche danger in Colorado. Two avalanches just today shutting down a major interstate. We have the track of this system, and here's ABC's kayna Whitworth. Reporter: Tonight, that winter storm bringing dangerous avalanches to the Colorado rockies. Late reports of vehicles trapped on highway 91. Avalanches today already trapping a tow truck in Vail pass, rupturing a gas line in copper mountain and shutting down part of I-07. I've been doing my business for about 30 years, and I've never seen it like this. Reporter: Crews deliberately triggering avalanches to try to reduce the risk. The Colorado avalanche information center says we're seeing historic activity. Reporter: Extreme or high danger in nine of ten backcountry Zones including aspen, Vail and Breckenridge. Authorities fearing more scenes like this one Sunday -- a wall of snow crashing down onto vehicles, including the golemon family. I don't see how you can say it was anything short of miraculous to survive the way we Reporter: Officials in Colorado declares historic avalanche conditions and warning people to stay away from prone areas. And here in California, we have so much snow that some ski areas will stay open through July. David? Wow. Kayna, thank you. That avalanche risk growing even worse tonight, as kayna that major storm now headed east, so, let's get to rob Marciano, tracking it for us tonight. Hey, rob. Reporter: Hi, David. More snow coming for the rockies and high winds with that powerful storm, so, we have the avalanche warnings remain in effect. Winter storm warnings up for Vail and aspen. Light snow for the Ohio river valley, but the big player is coming out of the rockies. That's going to be the severe weather player for Saturday, heavy snow north, heavier rain Chicago, Detroit, Pittsburgh, Philadelphia on Sunday, starting out as snow in new England, but then turning to rain. We're warming up. David? Rob, thank you. Next tonight, singer R.

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