(CBS/AP) An avalanche struck an informal snowmobile rally in Canada's Rocky Mountains, killing at least two people and leaving an unknown number missing at an annual gathering best known for its party atmosphere and stunt riding.
Rescuers sent helicopters over remote Boulder Mountain at daybreak Sunday to determine if conditions were safe for a full-scale ground search after operations were halted overnight when darkness fell.
Police also conducted a door-to-door search of hotel rooms Sunday to piece together how many people were missing from the Big Iron Shoot Out rally that drew about 200 people to the mountain.
Revelstoke Mayor David Raven said an avalanche warning had been in place for three weeks.
"A fresh snowfall overnight exacerbated that warning. I know people have been cautioned again and again," Raven told CTV Newsnet.
The avalanche occurred near Revelstoke, about 185 miles west of Calgary and about 250 miles northeast of Vancouver.
Royal Canadian Mounted Police now say two men were killed in an avalanche that struck a group of snowmobilers in British Columbia, and not three as believed in the chaotic hours after the slide.
RCMP Cpl. Dan Moskaluk also says police are more optimistic about the possible death toll after canvassing hotel rooms throughout the night to try and determine how many people are missing following the slide Saturday afternoon on Boulder Mountain, near Revelstoke, B.C.
He said Sunday police will still have to go back and re-check 40 rooms, and those rooms could have multiple guests.
He said 30 people were injured, one person critically. Nineteen of the injured have been released from hospitals and four transferred to hospitals in Calgary, Kelowna, Kamloops and Vernon, B.C., for treatment of more serious injuries.
Avalanche technicians flew over the area to test for stability Sunday morning and about 40 to 50 searchers will be on the mountain with five avalanche-trained search dogs.
Moskaluk said some hope remains that someone caught up in the slide could still be alive, but he indicated it might not be likely.
"I don't think we ever want to give up hope. Certainly there is faint hope at this time, however, being realistic we are referring to this as a recover/rescue situation."
The scope of the tragedy that had befallen the informal extreme-snowmobiling competition known as the Big Iron Shoot Out remained unclear.
One survivor, from Fort St. John, B.C., described a "big white wall of snow" coming down on his group of about 20 to 30 snowmobilers on the mountain in the Monashee Mountains, which are part of the Columbia Mountain range.
The man, who did not want to give his name, said they saw the slide coming and had only a few seconds to react.
He dove behind his snowmobile, and ended up partially buried. Members of his group dug him out.
Ervin McKeen, 62, from Nanton, Alta., was nearby when the avalanche occurred and he said there were about 150 people in the area where the snow came down.
It was pandemonium, said McKeen, who has been caught in three slides.
He said one man was screaming "Where's my son?" as he desperately searched the area. Snowmobiles were tossed around everywhere, he said Sunday.
The experienced backcountry user said he used his equipment to lead survivors with shovels to places in the snow where avalanche beacon signals - a piece of equipment that gives off an electronic signal from under the snow - indicated people might be buried.
Other survivors said the area looked like a "war zone" after the avalanche struck.
Kathy Berlingette, owner of the Smokey Bear Campground Resort in the area, said she had five guests who came to town for the event, an unsanctioned but increasingly popular informal gathering of those who enjoy snowmobiling in the deep snow of the B.C. backcountry.
All five of her guests survived the avalanche that struck around 3:30 p.m. in an area called the Turbo Bowl, at the foot of Boulder Mountain.
"One fellow that I was talking to said that it resembled a war zone," Berlingette said in a telephone interview.
"They're all very shook up, there were three fatalities. There were parents that took children up there to watch this event."
A spokeswoman for the Interior Health region said the area hospital called in all available staff and Revelstoke Mayor Raven said more than 20 people were treated for injuries on Saturday after being airlifted off the mountain. Interior Health said four people were transferred to larger hospitals in the region for treatment of more serious injuries.
The Canadian Avalanche Centre had a warning out for the area this weekend that the risk of avalanche was "considerable."
"Search and Rescue and the RCMP were out on site. They've got most of the people off that they know of now. The hospital's been very, very busy tonight," Raven said in a telephone interview Saturday.
He said authorities have "absolutely no idea" how many people may yet be unaccounted for. Estimates by those who were at the scene range from 50 to 150.
"It's an unsanctioned, unorganized event.... The RCMP are trying now to determine who was up there and how many and figure out who may be missing," Raven said.
Adam Burke, 20, a member of the Revelstoke Snowmobile Club, said his mother and many of his friends were up there at the time, but his mother was OK.
Burke said he chose not to go because of the dangerous conditions in the mountains this weekend.
"Today it was high risk and just the other day it was extreme," he told The Canadian Press in a telephone interview.
"I told everyone to shut the mountain down. ... Just how I've been riding and I've noticed a lot of slab avalanches and I've caused a lot of little stuff over the season and it's just progressively gotten worse.
"I told my mom to shut it down and don't have anything to do with this event because it's going to kick you in the ass."
Burke said the Big Mountain Shoot Out was started by a Calgary businessman several years ago, and got bigger over the years. It has a reputation for having a party atmosphere, with many riders and onlookers gathering to watch riders perform stunts, such as high-marking, where snowmobilers compete to see who can ride their high-powered sleds the highest up a steep slope.
There have been a few avalanche fatalities in the B.C. backcountry already this season but nothing compared to last winter, when there were two dozen deaths, including one slide that claimed the lives of eight snowmobilers near Fernie, B.C., in December 2008. There were 13 avalanche deaths the previous winter.
