SUMMIT COUNTY, Colo. (KDVR) – A microburst that occurred over Dillon Reservoir on Saturday afternoon separated a paddleboarder from the rest of his group and now rescue crews are searching for him.

According to officials with the Summit County Sheriff’s Office, the man is believed to have drowned.

“This is a tragic event. I have complete confidence in the professionals conducting this operation and that our search we will be successful,” Sheriff Jaime FitzSimons with the SCSO said.

Investigators with the SCSO said that members of the group that the now-missing man was with saw an incoming storm and tried to return to the safety of the Dillon Marina.

The storm arrived quicker than they could exit the lake and at that point, members of the group were separated as the rain began to fall and a microburst kicked up large waves.

Witnesses told investigators that when the microburst hit, they saw the man knocked off of his board, in the stretch of water between the Dillon Marina and the Roberts Tunnel shoreline, at which point he appeared unable to get his head above the water’s surface.

Those witnesses also said they saw a personal flotation device both unused and strapped to his board.

Rangers with the Summit County Sheriff’s Office were on the lake at the time and were quickly joined by members of the Summit County Sheriff’s Office Special Operations Section. Both units were able to quickly begin searching where the paddleboarder was last seen and additionally searched the nearby shoreline.

“I would ask that people be respectful and remain clear of the area being searched,” FitzSimons said.

This underwater search is still ongoing and the identity of the missing person hasn’t yet been released. FOX31 will update you once more information is released from Summit County officials.