At least eight people died after a strong avalanche hit a group of skiers in the Sierra Nevada mountains, California. One person remains missing. Sheriff Shannon Moon said rescue efforts are difficult due to a powerful winter storm. Fifteen skiers were buried by the avalanche; six were found alive. ‘‘We are still looking for one of the members at this time,’’ Moon told reporters. Families have been told the search has shifted from rescue to recovery. The avalanche occurred near the popular Lake Tahoe area, where heavy snow continues to fall. The Sierra Avalanche Center warns that more avalanches are likely as more snow adds to unstable conditions. The California Governor’s Office of Emergency Services is coordinating aid and rescue resources in Nevada County, where the incident happened near Castle Peak. Search teams rushed to the scene after a report that 15 people on a three-day trek were caught in the avalanche. Blackbird Mountain Guides said four of their guides were among those hit. ‘‘Our thoughts are with the missing individuals, their families, and first responders in the field,’’ the company stated. This deadly accident is the worst avalanche in California in over 40 years.