A “traffic jam” of climbers at the world’s highest peak has been the reported cause of at least 11 deaths in this year’s climbing season so far. As the videos above and below show, there are actually long queues of mountaineers waiting to move.

Four new deaths were reported on Mount Everest last Friday, including two Indians and a Nepali on the Nepal side and an Austrian climbing down the northern side in Tibet, The Hindu reported. Overcrowding due to a shorter window of suitable weather led to climbers getting stuck in a queue to the summit, which is located over 8,000 meters above the highest base camp on the mountain.

According to CNN, the area has come to be known as the “death zone” because climbers cannot spend more than a few minutes there without a supply of extra oxygen. A record 381 permits costing $11,000 each were issued by Nepal for the climbing season this year, leading to concerns that safety was being compromised for the sake of tourism in recent years.

Ameesha Chauhan, a survivor of the traffic jam, who was recovering from frostbite, told AFP, “I saw some climbers without basic skills fully relying on their Sherpa guides. The government should fix the qualification criteria. Only trained climbers should be granted the permit to climb Everest.”