Four skiers were killed and four others rescued after an avalanche Saturday in a backcountry ski area near Salt Lake City, police said.

The Unified Police Department of Salt Lake City received a hang-up call around 11:40 a.m. Saturday, and then received a report that there had been an avalanche in the Wilson Basin area with five people trapped, according to Sgt. Melody Cutler, a public information officer with the police department.

Two groups of skiers, one group of three and another of five, began skiing on the mountain at the same time and authorities think the avalanche was caused by the group skiing, Cutler said.

"Four of those skiers were able to dig their way out," Cutler said. "All four of the remaining are deceased."

The skiers range in age from early 20s to late 30s, according to Cutler. A Life Flight rescue service was called to transport the survivors out of the area, and a flyover was being conducted to determine whether it is safe for rescuers to remove the deceased tonight, Cutler said.

The location where the avalanche occurred is a "very popular backcountry ski area," Cutler told CNN, adding that it has "been under very high-risk avalanche conditions recently."

Wilson Basin is by Mill Creek Canyon, about 20 miles southwest of Salt Lake City.

The Utah Avalanche Center said in a tweet Saturday morning that there were "dangerous avalanche conditions."

Utah Gov. Spencer Cox responded to Saturday's deaths on Twitter, calling it a "terrible tragedy."

"We are grateful to the first responders and others who engaged in this rescue and recovery effort," Cox said. "With avalanche danger high right now, please exercise extreme caution."

Salt Lake City Mayor Jenny Wilson tweeted that she was "heartbroken."

"We deeply mourn the loss of life due to this devastating incident," Wilson said.

The four are the most recent in a string of deaths caused by avalanches in three states, bringing the number of fatalities to nine.

A Utah man was killed when he was caught in an avalanche near Park City Mountains Canyons Village resort a week ago, just a few miles from the site of Saturday's avalanche. The Utah Avalanche Center has already published a report analyzing the avalanche.

Three more skiers, who were all local officials, were killed in an avalanche in Colorado Monday. Their bodies were recovered Wednesday.

In New Hampshire, the body of a skier was recovered Wednesday after an avalanche in the White Mountain National Forest.

MILLCREEK, Utah — Four skiers are dead after an avalanche in Millcreek Canyon, which is in the Salt Lake City area.

The Unified Police Department of Greater Salt Lake said it received a "faint" distress call around 11:40 a.m. Saturday. Despite poor cell phone reception in the area, officers were able to determine that the slide happened in the Wilson Glade area of Wilson Fork. It is also near Alexander Basin and Gobblers Knob.

UPD later confirmed that four of the skiers were dead and four others were alive. All eight had avalanche beacons.

The medical status of the survivors was not immediately available, but officials say they were able to dig themselves out. The surviving skiers were also able to locate and dig out the other four, but they had already died.

Search and rescue teams from several agencies are working to recover the bodies in a way that will not further endanger crews from getting caught in another avalanche.

“We are heartbroken over the tragic news of four fatalities as the result of an avalanche in the Millcreek Canyon area this afternoon," Salt Lake County Mayor Jenny Wilson wrote in a statement. "We deeply mourn the loss of life due to this devastating incident.”

The incident is the first deadly avalanche in Salt Lake County this winter season. There were two others last month in the Park City backcountry: a skier in the Square Top area and a snowboarder in Dutch Draw, respectively.

Gov. Spencer Cox also issued a statement, writing on Twitter:

The Utah Avalanche Center reports that an avalanche was remotely triggered in the same general area just one day prior. Nobody was caught in it.

UPD says Millcreek Canyon is closed to recreation at least through Sunday, but restaurants and businesses in the canyon will still be open.

The victims' names have not yet been released, and the survivors' medical status is not known at this time.

This story was originally published by Jonah Napoli, Spencer Burt and Spencer Joseph at KSTU.