A fatal ski lift accident that occurred in the Blue Sky Basin area of Vail Resort has been deemed accidental, though authorities are still trying to determine what exactly happened.

Initial reports stated that Jason Varnish of New Jersey died of positional asphyxia after falling from a chairlift seat into a position where his coat was wrapped around his head and neck.

According to Denver Channel, the lift seat that Varnish was trying to use may have been flipped into an upright position, making it possible for the man to fall through. This flipping upright of lift seats can occur on some lifts during periods of strong wind, though it is uncertain if this is what happened in this case. The accident occurred on Chairlift 37, which Vail Resorts has claimed was functioning properly at the time of the incident, according to the Washington Post.

Ski lift deaths are very uncommon. The last ski lift-related death to occur in Colorado happened in December of 2016 at Granby Ranch when a mother was thrown from a lift.

The last week has been a deadly one in Colorado’s mountains, with multiple avalanche deaths, a skier death at Purgatory, a skier death on an Aspen half-pipe, and a Nordic skier death, in addition to the death on the Vail lift. This brings the total number of skier deaths during the 2019-2020 season to 11.