A search is under way for nine skiers missing after an avalanche in the mountains of California, where a huge storm has dumped heavy snow.
Officials said a group of 15 people were caught up in the avalanche on Castle Peak in the Tahoe area late yesterday morning.
Six skiers had been rescued "with varying injuries" yesterday evening, the Nevada County Sheriff's Office said, though mountain rescue teams battling treacherous conditions were still trying to find the others as snow fell and daylight faded.
Two of the rescued skiers were taken to a hospital for treatment.
Authorities previously said 16 people - four guides and 12 clients - were on the trip, before revising that number down to 15.
"Due to extreme weather conditions, it took several hours for rescue personnel to safely reach the skiers and transport them to safety where they were medically evaluated by Truckee Fire," the sheriff's office said in a statement.
"The search is ongoing, pending weather conditions."
Officials had said 46 emergency first responders were involved in the search, including "highly skilled rescue ski teams" from both Boreal Mountain Ski Resort and Tahoe Donner's Alder Creek Adventure Center, who were dispatched to rescue the six known survivors.
A powerful storm packing several metres of snow continued to pummel the Sierra Nevada mountain range throughout the day, with forecasters warning of white-out conditions.
Experts had warned that the risk of avalanches was expected to extend into today.
"HIGH avalanche danger exists in the backcountry. Large avalanches are expected to occur Tuesday, Tuesday night, and into at least early Wednesday morning across backcountry terrain," the Sierra Avalanche Center said.
"HIGH avalanche danger might continue through the day on Wednesday."
The National Weather Service said parts of the Sierra above 1,000 metres could see up to 2.4m of snow over the next 48 hours, with gusts of wind as strong as 90km/h.
Sheriff's office Captain Russell Green told local media station KCRA that officials discourage people from backcountry skiing.
"People go out and use the backcountry at all times," Cpt Green said. "We advise against it, obviously, but I wouldn't say that it's uncommon. Not that it was a wise choice."
The Colorado Avalanche Information Center has tallied six US avalanche fatalities so far this season, including one in Castle Peak in January.
