UPDATE (2:15 p.m.): An Excel Energy spokeswoman said that power has now been restored to 92 percent of the roughly 23,000 homes in Summit, Park and Lake counties that experienced sustained power outages. Around 1,800 are still without power.

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The first major snowstorm of the season came in force overnight Sunday, battering the mountains with heavy, wet snow that clogged traffic, canceled school and left more than 10,000 High Country homes without power into Monday morning.

Simultaneous closures at major choke points on Interstate 70 at the Eisenhower-Johnson Memorial Tunnel and Vail Pass left drivers marooned in Georgetown and at a shelter in Vail, which soon filled to capacity.

“It’s been a long morning,” said Colorado State Patrol Sergeant Patrick Williams. “Welcome to winter, right?”

Despite the mayhem and lengthy mop-up efforts, which started to wrap up at around 9:30 a.m., Williams said he was not aware of any serious injury or fatality crashes in the Summit County or Vail Pass area.

Still, a constellation of crashes, slide-offs and then power outages grounded travel in the mountains to a halt throughout the night.

“We were busy all morning and night,” Williams said. “No one was going east or west until about (8:00 a.m.)…. Just your typical warm, wet Summit County fall.”

The timing of the storm is not wholly unprecedented, but it was unique in that it lingered over Summit and Eagle counties all night, maximizing accumulations here.

“It was a very slow-moving storm that happened to be in the right place — it was pure luck,” said meteorologist Joel Gratz of OpenSnow.com. “What’s special was the Jetstream wasn’t moving much, and some areas were getting one to two inches per hour last night.”

Gratz said late Monday morning that the break in snowfall would end in the afternoon but the storm would then taper overnight.

The road trouble began in earnest Sunday evening as the snow began to stick at around 6 p.m. The National Weather Service warned of accumulations up to 8 inches in some areas.

Snowfall intensity will increase again over the N/Cent Mtns later this morning & aftn. Heaviest snowfall above 9000ft & west slopes. #COwx pic.twitter.com/do8ERhivpq — NWS Boulder (@NWSBoulder) October 2, 2017

I-70 closed in both directions at the Eisenhower Tunnel at around 6:30 p.m. Sunday due to multiple crashes. It re-opened an hour later but had to periodically close Monday morning due to power outages and the inability of Colorado Department of Transportation’s backup generators to compensate, Williams said.

The outages began at around 8 p.m. on Sunday night and affected nearly 45,000 homes in Summit, Park and Lake counties, an Xcel Energy spokeswoman said. Roughly half of those lasted less than five minutes, but as of 11 a.m. there were still more than 10,000 homes without power.

The spokeswoman wasn’t able to immediately clarify how many homes in Summit County specifically were without power. She said that 56 crews were working in the mountains and had restored power to more than 14,000 of the 23,000 homes that suffered sustained outages.

The outages prompted the Summit School District to cancel all classes Monday, according to a 7:50 a.m. Twitter post.

#ssdedu DUE TO POWER OUTAGES THROUGHOUT #SUMCO, SUMMIT SCHOOL DISTRICT IS CANCELING SCHOOL for Monday, October 2 — SummitCountySchools (@summitk12) October 2, 2017

Multiple crashes at Vail Pass and near Copper Mountain left that area of I-70 closed throughout most of the night, and travellers were housed at a shelter in a Vail municipal building. By early Monday morning, that shelter was full, and the Vail Interfaith Chapel was designated a backup.

U.S. Highway 6 was not spared either, with Loveland Pass shutting down early Monday morning due to multiple jackknifed semis and staying closed until 11 a.m.

The storm, however, was more good news for ski areas, some of which had already gotten an early jump on snowmaking. Mid-mountain snow stakes at some showed accumulations of 10 to 15 inches.

All took to social media with posts boasting the fresh powder and ski runs covered top-to-bottom, if only with thin layers.

Arapahoe Basin and Loveland ski areas expected to open in mid-October, while Copper Mountain, Keystone Resort and Breckenridge Ski Resort are slated for early November.

Still, while the storm was exciting for skiers and riders, Gratz cautioned that storms this early in the season don’t presage a good year for snow.

“October snowfall has very little correlation for the rest of the season,” he said. “There are other signs that are positive, but this is really not a sign that the rest of the of the season will be incredible.”