As many as 10 skiers were missing after an avalanche near Truckee, California, authorities said Tuesday.

An avalanche was reported in the Castle Peak area near Truckee at about 11:30 a.m., which affected a group of four mountain guides and 12 other skiers, the Nevada County Sheriff’s Office said in a news release.

The sheriff’s office said at least six skiers survived the avalanche and remained at the site as of about 3:45 p.m., where they were still awaiting rescuers. The other 10 people were unaccounted for, the sheriff’s office said.

Rescue ski teams from Boreal Mountain Ski Resort and the Alder Creek Adventure Center, another local recreation and ski organization, were headed to the area try to find the six survivors.

The weather in Truckee has been treacherous, with blizzard conditions impeding search and rescue efforts.

The Boreal Mountain Ski Resort, which is near Castle Peak, was reporting about 30 inches of snowfall over the past 24 hours. Castle Peak is a popular backcountry skiing destination along Interstate 80.

Avalanche danger was high on Tuesday.

“Travel in, near, or below avalanche terrain is not recommended today,” the The Sierra Avalanche Center wrote in a bulletin issued before the reported avalanche. “A widespread natural avalanche cycle is expected over the next 24 hours. Large avalanches may run through treed areas. If attempting travel today in non-avalanche terrain, be certain that there are no steeper slopes connected to the terrain you are traveling, either above or to the side.”