PHOENIX — Winds howled overnight in northern Arizona, knocking out power to thousands of homes and the National Weather Service office in Flagstaff.

Data from the weather service showed the highest wind gusts at 85 mph off Interstate 17, about halfway between Flagstaff and Phoenix, early Wednesday morning.

The Arizona Department of Transportation said it took a rare step and preemptively closed major roadways across the state as winds sent snow blowing.

A more than 200-mile stretch of Interstate 40 was shut down in both directions from western Arizona to the New Mexico state line.

The National Weather Service said a wind gust of 51 mph Wednesday at Tucson International Airport was the strongest February wind gust in the last 50 years.

Authorities said wind gusts of up to 50 mph resulted in 66 flights being canceled and 45 others delayed at Phoenix Sky Harbor International Airport by 9 a.m. Wednesday.

More than 5,700 homes were without power Wednesday morning in the Phoenix metro area with 10,000 homes affected in the Flagstaff area, where snowfall and wind gusts of 68 mph was causing white-out conditions.

The National Weather Service said up to a foot of snow was expected by Thursday morning in elevations above 5,000 feet (1,524 meters) in northern Arizona.

Some schools in Flagstaff announced closures Tuesday ahead of the storm.

The weather service said a high wind warning was in effect for most of New Mexico through Thursday morning, with gusts of up to 70 mph (113 kph) possible.

The storm system swept through southern Nevada on Tuesday, causing power outages and flight delays at Las Vegas airports.