An unidentified man appears to have crashed while snowboarding on an expert run before hitting a tree in a fatal collision at Eldora Mountain Resort, according to the Boulder County Sheriff’s Office.

The crash happened at about 10:35 a.m. today, March 7. The snowboarder, believed to be 23 years old, was on the Mule Shoe run at the time of the crash. He was wearing a helmet.

The mountain’s ski patrol found the man unconscious and not breathing shortly after the crash and immediately started CPR, according to BCSO.

The man was pronounced dead at the scene by a paramedic who was advised by an emergency room doctor. An ambulance from American Medical Response responded to the scene, as did Nederland Fire Department and the county coroner’s office.

Authorities are withholding the man’s identity until his relatives are notified.

Update: Officials originally said the deceased man had been skiing, but later informed the Boulder Daily Camera that he was snowboarding.