Several feet of snow were expected to fall in parts of New Mexico and Colorado over the next three days in what meteorologists said could be the worst blizzard to hit the region in decades, as the authorities warned of dangerous road conditions and power outages.

Tens of thousands of people in New Mexico are without power as the first major winter storm of the season rolled across the northern two-thirds of the state.

There’s one more push of snow in store in the coming days, said Joel Gratz, meteorologist and founder of OpenSnow, a snow forecasting app. He said tomorrow evening and especially into Saturday, a storm that has been stalled and swirling south of Colorado will start moving.