Mammoth Mountain was closed Saturday after a "major avalanche."Mammoth Mountain Ski Patrol had been doing avalanche mitigation work about 10:15 a.m. in a closed area of the resort when an avalanche was released and traveled to areas open to the public, a statement from Mammoth Mountain said.Three people, including a Mammoth Mountain employee, were partially buried but were able to free themselves without injury, the statement said.Six employees in the closed area were also partially caught, but they also were able to free themselves and suffered only "minor injuries," according to the statement.A search and rescue operation using dogs and transceiver detectors was launched "within minutes," the statement said, but no one else was found buried.Ryan Williams, who took video of the area just minutes before the avalanche, said the snow was already deep before the avalanche hit."One guy was buried up to his chest area, and that was completely before the avalanche, so the snow was very deep," he said.The resort remained closed all day Saturday "to focus all efforts on the site."Nearly 200 employees, first responders and guests contributed to the effort, the statement said.Local police described the event as a "major avalanche" and asked people to steer clear of the area Saturday morning.In their statement, Mammoth Mountain representatives said they would return to normal operations Sunday.