Three climbers have died on Mount Everest and a fourth person is missing, authorities said Sunday. An American climber identified as Roland Yearwood, a doctor from Alabama, died near the mountain’s summit on Sunday. He was climbing the mountain for a second time after surviving an avalanche caused by an earthquake there in 2015. Slovak climber Vladimir Strba was also reported dead after scaling the mountain on Sunday, and an Australian climber, Francesco Enrico Marchetti, died on the Tibet side of the mountain after getting altitude sickness. Indian climber Ravi Kamar has been reported missing after getting sick on his way down from the summit on Saturday. Kamar never made it to the nearest camp, while his Nepalese Sherpa guide managed to drag himself to the camp and report Kamar missing. A rescue team was still searching for Kamar on Sunday, authorities said. The Nepalese Tourism Department reported a spike in the number of permits issued to climb the mountain this year, with 375 foreigners granted permission to go up against the world’s tallest peak, according to the Washington Post. Authorities attributed the high demand to the fact that many climbers who’d previously applied for permits were unable to use them after avalanches in 2014 and 2015.