Utah Avalanche Center wrote:Do Cell Phones Interfere with Beacons?
Yes! Especially in SEARCH mode. Several reports from failed or severely disturbed and delayed rescue action in the last years have shown that electronic equipment can have a very unpredictable and severe influence on avalanche rescue transceivers.
Basic recommendations:
In SEND (transmit) mode keep items like cell phones, radios, iPods, and cameras with wireless capability at least 20cm away from your transceiver. Further is better. If your cell phone is on, it should be in Airplane Mode to minimize interference. Better yet, turn off all electronics and put them in your backpack (except your transceiver, obviously).
In SEARCH mode, all electronics should be at least 50cm away from your transceiver, including electrically heated gloves. Turn off all cell phones.
Also clearly demonstrated in this video (linked from the above article)...