LAKE LOUISE, Alta. -- RCMP say two American snowshoers are presumed to have died in an avalanche near Lake Louise in the rugged mountains of Banff National Park.

Cpl. Curtis Peters says two people from Boston did not check out of their hotel Tuesday in Field, B.C., and their vehicle was found at a trail head on Highway 93, a road known as the Icefields Parkway.

"We believe they had gone snowshoeing and subsequently got caught in an avalanche," Peters said in an interview Wednesday. "We do not know for certain, but we presume that they are deceased."

Parks Canada said safety specialists found snowshoe tracks near the rental vehicle that led to avalanche debris. They found no tracks coming out.

Tania Peters, a Parks Canada spokeswoman, said the avalanche risk is so high it was too dangerous to send a search team to the avalanche itself.

A helicopter that flew over the area picked up signals from two avalanche transceivers -- small electronic devices that people wear that send out radio signals that searchers can home in on to rescue buried people.

"We were able to do a flyover in a helicopter and we did pick up two transceiver signals leading us to believe that the two people are in fact buried in the debris," Peters said.

"On behalf of Parks Canada we would like to say that our thoughts are with the family and friends of these individuals. We are making every effort to get into the area and conduct a search, but we have to do that safely."

RCMP said the families of the missing people have been notified and their identities will not be released.

Parks Canada and RCMP said they were treating the search as a recovery operation.

Avalanche conditions were listed as high, one level below extreme, and parts of Highway 93 were closed Wednesday due to the danger.

The region was also under a weather alert that warned of a possible storm that could include heavy snow.

Avalanche Canada's website indicates that four people have died in snowslides in the British Columbia mountains in the last three months.

-- By John Cotter in Edmonton