Police say a fourth person has died and three people are still missing following a double avalanche in the Swiss Alps on Sunday. Police in Bern canton (state) said Monday the fourth victim died of injuries in the hospital. Three people were confirmed dead Sunday after a group of skiers and then the rescuers who came to their aid were hit by avalanches in the Diemtig Valley about 25 miles (40 kilometers) south of the capital Bern. Among those killed was an emergency doctor who was part of the initial rescue team. It was unclear Monday whether officials would be able to resume the rescue and recovery operation that was halted at nightfall. Officials are warning of heightened avalanche risk in the Swiss Alps following heavy snowfall. 