The search for a man who fell off of a boat near Sentinel Island in Lake Mead was called off before 7 p.m. on Thursday due to winds causing high waves.
Park officials said the man disappeared at approximately 4 p.m. Crews searched for the man for about two hours.
The National Park Service said the missing person is a 35-year-old from Chicago. He jumped into the lake to swim and was not wearing a life jacket.
The search for the man will resume at daybreak on Friday.
Sentinel Island is near Castle Cove on the Arizona side of the lake.
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