HOUSTON, United States

Eight skiers were killed in an avalanche in Lake Tahoe, California, and a ninth is presumed dead, according to media reports Wednesday.

Authorities said the group was on a day-trip skiing expedition Tuesday when the avalanche struck.

Six members of the group survived, but officials said one person remains missing and is believed to be dead.

“We did have conversation with the families of the folks that are still outstanding and let them know that our mission went from a rescue to a recovery,” Nevada County Sheriff Shannan Moon told reporters. “It’s a difficult conversation to have with loved ones.”

Officials said the avalanche stretched roughly the length of an American football field, about 100 yards (91.44 meters).

Recovery efforts have been hampered by near white-out conditions caused by heavy snow and strong winds, leaving the bodies of the eight confirmed victims and the ninth, who is presumed dead, at the scene. Significant avalanche risks remain in the area.

“The risk is still as high with the mission moving to a recovery,” said Moon. “We want to really make sure that our first response responders are safe.”

Placer County Sheriff Wayne Woo, whose deputies are assisting in the operation, said it may take time before all nine bodies are recovered.

“We’re all so committed to seeing this through until the end,” Woo said. “At this point, I’m going to have to wait for, hopefully, a decent break in the weather and make sure we get every last soul off that mountain.”