Airline passengers are familiar with hearing the obligatory "please turn off all electronic devices before takeoff." Soon, backcountry skiers may follow the same drill. An investigation into a fatal avalanche in Pra-Loop, France, revealed that a skier's cell phone may have disrupted rescuers' avalanche beepers. "Beacons work on a frequency of 457 megahertz. If you have another electronic device in use close to the beacon, it might interfere," says Cyril Shokoples, owner of Rescue Dynamics in Edmonton, Alb. In other words, when you're in the backcountry, keep the cell phone off¿saving it for emergency use¿to prevent the possibility of interference if a search is necessary. "Beacons are infinitely more important than a phone," says Bruce Edgerly, vice president of Backcountry Access, a Boulder, Colo., safety-gear manufacturer. "If you don't get to a buried skier within 15 minutes, forget about it. Why would you spend five seconds on a call when you could be searching?"