Several people have been killed, dozens are injured and many more could be trapped in an avalanche on a mountain in southeastern B.C.

Hundreds of people watching and participating in the Big Iron Shootout, an annual snowmobiling event on Boulder Mountain, near Revelstoke, were caught in the slide.

Reports indicate the avalanche struck at about 3 p.m. local time Saturday.

One official told CBC News that three people are dead, two others are in critical condition and more than a dozen others were injured in the slide. It is not clear how many more people are missing.

The mountain has been shut down and a massive rescue operation is underway. Search-and-rescue helicopters and avalanche dogs are working to recover the injured.

"I know that the RCMP are up there with a number of their members doing searches and that they've got dog units … and the local search and rescue group," Revelstoke Mayor David Raven said. "We also have the ski patrol from Revelstoke Mountain Resorts available and going up."

He said the provincial government has already reached out to offer its support.

"I have been contacted by Kash Heed, the solicitor general, and the province is fully behind all of our efforts and we appreciate all of the help we have now, and it's another trying event for Revelstoke."

Raven said he wasn't sure how many people were in the area at the time of the slide, but he did say the Big Iron Shootout is an unorganized event "that's been a problem for years."

According to the Canadian Avalanche Centre, there have been 10 avalanches in the area since Friday, when the CAC issued an extreme avalanche warning for the area. It advised people to stay away from any defined avalanche terrain and steep slopes.

On Feb. 15, an Alberta man was killed in an avalanche while snowmobiling on Eagle Mountain near Revelstoke. Another Alberta man died in an avalanche while skiing near Rossland, B.C., in early January.

Revelstoke is approximately 300 kilometres west of Calgary, and about 400 kilometres northeast of Vancouver.

Read more: http://www.cbc.ca/canada/briti.....z0i7RopsgL

Earlier report:

Reports indicate the avalanche struck at approximately 3 p.m. local time Saturday.

There are reported fatalities and it's believed several people may have been buried by the avalanche. One official told CBC News two people may have been killed and at least seven more were critically injured.

Several people have been injured and many more could be trapped in an avalanche on Boulder Mountain in Revelstoke, B.C., officials say.

Several search-and-rescue helicopters, along with medical personnel, are en route.

According to the Canadian Avalanche Centre, there have been 10 avalanches in the area since Friday, when the CAC issued an extreme avalanche warning for the area. It advised people to stay away from any defined avalanche terrain and steep slopes.

On Feb. 15, an Alberta man was killed in an avalanche while snowmobiling on Eagle Mountain near Revelstoke. Another Alberta man died in an avalanche while skiing near Rossland, B.C., in early January.

Revelstoke is approximately 300 kilometres west of Calgary, and about 400 kilometres northeast of Vancouver.