Crews have pushed through mountainous wilderness in California near Lake Tahoe during a snowstorm to rescue six backcountry skiers who survived an avalanche but were trapped by its snow and ice. Nine others from their tour group remain missing. The Nevada County Sheriff’s Office says two of the six were taken to a hospital for treatment. The sheriff’s office says there were 15 skiers on the trip, not 16 as initially believed. Extreme weather conditions in the Northern California mountains are slowing the rescue effort. It took crews several hours on Tuesday to reach the skiers and take them to safety, where they were evaluated by the Truckee Fire Department.