Ada County Sheriff's deputies say a Boise man who was not wearing a helmet crashed his motorcycle Friday night when his bike hit a basketball-sized boulder. The 51-year-old rider lost control of his 2010 BMW motorcycle and crashed.
The victim suffered extensive head injuries and died instantly.
Law enforcement officials reduced traffic on Highway 21, about three-quarters of a mile above a diversion dam, through much of the evening while they investigated the crash.
The motorcyclist's name has yet to be released by the Ada County Coroner's Office.
Meanwhile, Kootenai County Sheriff's deputies say a Moscow man died when his motorcyle collided with a van on U.S. Highway 95.
Witnesses said 63-year-old Richard Nagy was traveling northbound on U.S. 95 when his motorcycle slammed into the rear of a cargo van which was making a left-hand turn.
Nagy was wearing a helmet at the time of the crash.