UPDATE JAN 6

A snowmobiler, identified as Chris Scott Thomason, who was 42 years old, died following an avalanche on Monday.

A group of people was returning from Castle Peak when they triggered an avalanche on the backside of a mountain, burying Thomason.

"During their return trip back to Johnson Canyon, one of the subjects was taking a high line along the mountains, dislodged some snow, and likely caused the avalanche," said Sergeant Dustin Moe with the Nevada County Sheriff's Office.

Thomason was visiting from Bend, Oregon, and was accompanied by two other people, along with two other individuals from the local area. The group was all prepared for backcountry exploration, wearing protective equipment, including beacons and transceivers.

According to the Nevada County Sheriff's Office, in an online post, after the group found Thomason by tracking his beacon, they immediately started digging him out.

Eventually, the group did pull him out of the snow and started CPR.

Another person, not from the group, who was an off-duty Truckee Fire medic, took over CPR efforts and tried to save his life.

Deputies say despite the efforts to save Thomason's life, he had passed away.

"For the friend-on-friend rendering aid," Sergeant Moe said, "there was a quick response, and they took action immediately. So they did great out there."

The Sheriff's Office says thank you to the nearly 50 people who helped aid in the rescue operation. All other people have been accounted for and are safe. Deputies say the search concluded on Monday evening.

Visit the Sierra Avalanche Center website for more tips on avalanche awareness and emergency preparedness. 

ORIGINAL STORY:

A snowmobiler has died following an avalanche in the vicinity of Johnson Canyon and Castle Peak in Truckee.

It happened around 2:19 p.m., according to a post from the Nevada County Sheriff's Office on Facebook.

The initial call reported an avalanche that happened among a group of snowmobilers, with one of them unaccounted for.

That snowmobiler was found buried under the snow several minutes later and did not survive, despite lifesaving efforts.

There are around 45 emergency responders on scene, with that number expected to grow.

The Nevada County Sheriff's Office is on scene in partnership with Truckee Fire and North Truckee Fire.

The scene is still active, with emergency responders working to safely extract the victim and confirm there are no other victims.

Further avalanche activity is possible, and people should avoid the area.