The incident occurred while off-piste skiing in an area northwest of Lake Tahoe on Tuesday.
Six people have been found alive, two of whom have been taken to hospital. One person is still missing.
The avalanche was triggered by storms in the area.

Eight of nine skiers missing after an avalanche in Northern California, United States, have been found dead, police say.
The incident occurred while off-piste skiing in an area northwest of Lake Tahoe on Tuesday.
Six people have been found alive, two of whom have been taken to hospital. One person is still missing.
The avalanche was triggered by storms in the area.