With the first significant snowfall in weeks bearing down on the Sierra Nevada, resort companies are suspending ski operations over concerns about COVID-19.

Vail Resorts, which operates Northstar, Heavenly and Kirkwood resorts in the Lake Tahoe region, made the announcement Saturday afternoon.

Within hours of the Vail announcement, Alterra Mountain Co., which owns Squaw Valley Alpine Meadows and Mammoth Mountain, made a similar announcement.

In the statement, Vail CEO Rob Katz wrote, "we have made the difficult decision to suspend the operations of all our North American mountain resorts and retail stores beginning Sunday, March 15, 2020 through Sunday, March 22, 2020 and will use that time to reassess our approach for the rest of the season."

Katz also wrote employees would continue to be paid.

"All our scheduled employees, both seasonal and year-round, will be paid during this upcoming eight-day period, without needing to use any vacation or sick time," Katz wrote. "Their commitment to our company and guests during this uncertain time has been unwavering and I am personally grateful beyond words."

The Alterra announcement from CEO Rusty Gregory said the company would suspend resort operations beginning Sunday, "until further notice."

Gregory wrote, "Alterra Mountain Company will suspend operations at our 15 North American ski resorts, starting the morning of Sunday, March 15, until further notice. All lift operations, food and beverage, retail and rental services will be closed until further notice."

The Alterra announcement did not say whether employees who lose hours would continue to be paid.

Sugar Bowl in Truckee, Calif., made a similar announcement Saturday afternoon.

"As we’ve continued to closely watch and adjust our operations to the rapidly changing world-wide impacts of the coronavirus (COVID-19), we’ve made the decision to suspend operations at Sugar Bowl and Royal Gorge until further notice," the announcement stated. "Similar to other resorts in the region, we were committed to operating the resort until new information guided our decisions."

Late Saturday Boreal Mountain Resort, owned by Powdr Corporation, followed suit with a post stating the resort would close Sunday until further notice. Sierra-at-Tahoe said in an announcement it would also close Sunday for a minimum of 72 hours.

The announcements come as resorts across the skiing and snowboarding world have been grappling with how to ensure they're safely and responsibly dealing with the spread of the virus, which the World Health Organization considers a pandemic.

While some resorts say they plan to stay open, concerns about the spread of the virus have been increasing among officials and the general public.

"This was not an easy decision to make, as we deeply considered the impact it will have on our guests, employees, and the people and businesses in our communities," Katz wrote. "Please know that this has been a fast-moving, constantly developing situation with new information from our communities coming to us by the day, if not by the hour, and we are trying to react as quickly as we can."

Dave Amirault, a former ski resort marketing executive and industry observer, said the pandemic related closures are unprecedented.

"This is uncharted territory," he said. "It is better to be cautious than to put people in danger."

Amirault said once Vail suspended operations it was clear others would soon follow suit. And they did.

"What you do is follow the lead of the big boys, which is what we are seeing happening right now," he said.

Amirault said it would be difficult for small mountain towns to cope with the economic fallout, but added that the closures are happening closer to the typical end of the ski season than the beginning.

He also urged understanding among skiers and snowboarders.

"It is important for everyone to realize there will be more ski seasons," he said.

Still, some resorts have said they will continue to operate, for now.

Mike Pierce, spokesman for Mt. Rose Ski Tahoe in Reno, said the resort plans to continue operating, albeit with intensified disinfectant measures it implemented before the Jan. 20 Martin Luther King Holiday.

They include increased frequency of disinfection on high touch surfaces, increased availability of hand sanitizer, gloves for all cashiers and options for people on the mountain to choose to ride alone or with family on chairlifts.

“With the COVID-19 public health issue, our team is vigilant in its efforts to maintain a high standard of cleanliness and is committed to employee awareness and training,” the resort’s coronavirus post stated.

Pierce said Mt. Rose is monitoring the situation daily.

With a late-winter storm bringing much-needed snow at the tail end of a dry season, resort operators are eager for more skier and snowboarder traffic.

But the storm coincides with increasingly dire news about the spread of coronavirus in California and, to a lesser extent, Nevada.

State health officials in California have called for the suspension of indoor or outdoor gatherings of 250 or more people. It’s advice echoed by officials in Placer County, which includes a portion of the Lake Tahoe area.

Resort operators canceled events but some in the public called on them to take stricter measures such as shutting down for the season.

“We have a responsibility to try to do everything we can to slow the spread of this illness and this is the opposite,” said Michele Dauber, a former Yosemite wilderness ranger with a home in Bear Valley, Calif.

Dauber tweeted her displeasure about resorts encouraging people from the Bay Area, a coronavirus hotspot, into mountain communities that haven’t yet seen community spread of the virus.

“It is really important to control the spread of the virus in rural areas that even in good times have little access to quality health care,” said Dauber, who is also a Stanford law professor and sociologist.

Across the country, resorts including Taos Ski Valley in New Mexico, Jay Peak Resort in Vermont and Shanty Creek Resort in Michigan have decided to close for the season.

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

"Skiers are pretty well covered from head-to-toe and being outdoors, the contamination factor is minimized," said Tom Watkinson, spokesman for Telluride Ski Resort in Colorado.

This is a breaking news story and will be updated.