SALT LAKE CITY (AP) — As ski resorts across the United States grappled with how to help prevent the spread of the coronavirus without having to close, industry giants Vail Resorts and Alterra Mountain Company decided Saturday they would shutter 49 of North America's most well-known resorts.

Vail Resorts said it would shut down its 34 resorts for at least one week before reassessing while Alterra is closing its 15 until further notice. The Telluride Ski Resort in Colorado and the Aspen Skiing Company announced Saturday night that they will close ski operations, too.

The closures marked a sudden change of course after the majority of the country's resorts vowed earlier Saturday to stay open during the crisis while taking measures to prevent the spread of the virus.

Vail's resorts include Vail, Keystone and Breckenridge in Colorado; Park City Mountain Resort in Utah; Heavenly, Northstar and Kirkwood in the Lake Tahoe area of California and Nevada; Stowe Mountain in Vermont; and Whistler Blackcomb in British Columbia, Canada.

Alterra's include Steamboat and Winter Park in Colorado; Squaw Valley, Mammoth and Big Bear Mountain in California; Crystal Mountain in Washington; Stratton and Sugarbush in Vermont; and Deer Valley and Solitude in Utah.

Vail Resort CEO Rob Katz apologized in a news release for the short notice and especially to guests already at the resorts or planning to come this week. He acknowledged it may seem confusing considering earlier announcements.

“This decision provides a pause for the entire ecosystem of our mountain resort communities," Katz said. “It gives everyone the time to assess the situation, respond to ever-changing developments, and evaluate the approach for the rest of season, if we believe it is advisable or feasible to re-open.”

Alterra CEO Rusty Gregory also apologized but called it a decision in the best interest of the guests.

Both companies promised to work with skiers who had tickets or plans to come.

The Telluride Ski Resort said it decided to close immediately after learning that Colorado Gov. Jared Polis planned to issue an executive order closing the state's ski resorts. Late Saturday, the Aspen Skiing Company announced it was closing ski operations at Aspen Mountain, Aspen Highlands, Buttermilk and Snowmass because of Polis' order.

"We understand that this impacts a huge number of people. Our employees, guests and the community as a whole," the company said in a statement. "We are working now to address all of these issues and will work with each of these groups to minimize the impacts where we can.”

The company added the plan will be to “conduct some limited on-mountain maintenance to potentially have a limited late-season opening if circumstances allow. We are all skiers at heart and we understand the therapeutic nature of our shared passion.”

In issuing his order Saturday night, Polis said: “It is with a profound sense of pain and grim responsibility that I take the agonizing action that this moment demands. I take solace in knowing that while we will be temporarily closed for business, we will be saving the lives of hundreds, perhaps thousands of Coloradans in the days and weeks ahead.”

In California, the Squaw Valley Alpine Meadows ski resort announced late Saturday night that it will suspend operations starting Sunday.

“We sincerely apologize for the inconvenience this short notice will undoubtedly create. We look forward to welcoming you back to the mountains as circumstances improve," the company said in a statement.

The developments followed closures announced earlier by a trio of smaller resorts: Taos Ski Valley in New Mexico, Jay Peak Resort in Vermont and Shanty Creek Resort in Michigan. Taos will close for the season starting March 22, while Jay Peak and Shanty are closing for the season starting this weekend.

The other resorts that remain open are closing enclosed gondolas or aerial trams while others are encouraging skiers to ride lifts with only people they know as they adhere to social distancing guidelines.

Nearly every resort is promising extra cleanings of public spaces, more hand sanitizer stations and vowing to follow guidelines from the Centers for Disease Control and Prevention.

Still, some ski resorts are touting the popular winter activity as a relatively safe option for diversion as concerts, sporting events and museums close.

Avid back-country skier Michele Dauber strongly believes that resorts should be shut down to contain the spread of the virus.

“This is why Disneyland closed. This is why cruises don't make sense. A ski resort is just a cruise ship in the snow,” said Dauber, who has a house in the Bear Valley area in California and is a professor at Stanford University. “People are just constantly wiping their noses and they're wearing gloves so hand sanitizer isn't the issue."

Steve Clawson, a 57-year-old controller for the Denver Public Schools, went skiing for about six hours at Vail on Saturday. His plan was to head over to Breckenridge on Sunday. But as he made his way to the parking lot, his wife called and informed him of the news from Vail Resorts.

He was bummed his ski plans got dashed, but he understood.

“We all need to do what we need to do to help prevent the spread,” said Clawson, who canceled an upcoming trip to Las Vegas because of concerns over the virus. “Everybody is taking a hit. Vail needs to take a hit, too, and I guess I need to take the hit of not being able to ski. I'm OK with that.”

He added: “We have to look out for our medical professionals. If we're not stopping the spread, our hospitals are going to be inundated.”

A bartender in the Utah ski town of Park City tested positive for coronavirus, Utah state health officials said Saturday. A county health official said he would not recommend shutting down the nearby resorts, but cautioned against traveling to the area. One of Colorado's first cases was a man in his 30s visiting Colorado on a ski vacation.

The coronavirus, deemed a pandemic by the World Health Organization, infected more than 150,000 people and killed over 5,700. The disease for most people causes only mild or moderate symptoms. For some, it can cause more severe illness. The vast majority recover.

Jackson Hole in Wyoming closed its aerial tram and limited the number of people in gondolas. Mammoth in California said it planned to keep its gondolas half full and get rid of some chairs and tables in lodges to keep guests a safe distance apart. Powder Mountain in Utah ceased snowcat skiing because of tight quarters inside the vehicles.

Whiteface Mountain Ski Resort near Lake Placid in New York has closed its gondola and is limiting how many people are on lifts. The resort is also allowing only half the amount of people normally allowed at indoor facilities.

The U.S. Ski and Snowboard organization said Thursday all upcoming competitions in the United States had been canceled.

Resorts social media accounts were a mix of news about measures being taken to address the coronavirus and happy pictures and videos of skiers carving through fresh snow.

Powder Mountain in Utah posted a picture of a small group of skiers in lift line surrounded by pristine snow-capped trees and mountains around him with the caption: “Good morning and happy Saturday from Powder Mountain! Get outside and take advantage of the remaining winter days."

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Graham reported from Denver.

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