The avalanche occurred around 4 p.m., and the two survivors, Ian Laing and Patrick Leslie, used a satellite device to send a distress call, the statement said. Deputies from the sheriff’s department, together with local search and rescue volunteers, were able to reach the remote area by snowmobile. The authorities found the survivors, who were evacuated that evening, but were not able to continue searching at night because of hazardous conditions, according to the statement.