The 56-year-old man fell and suffered head injuries while hiking about eight miles northeast of Spada Lake on a trail near Williams Creek at an altitude of 2,500 feet, said Lt. A.J. Bryant of the Snohomish County Sheriff's Office.
He was accompanied by two other people. One stayed with him and the other hiked out for assistance.
The Snohomish County sheriff deployed a helicopter to rescue the man Sunday, but it had to turn back due to weather conditions and safety considerations.
By Monday morning, the man had died, said Shari Ireton of the Snohomish County Sheriff's Office. His body was taken to the nearest ranger station for transfer to the Snohomish County Medical Examiner.
The man's name was withheld pending notification of his next of kin.
Spada Lake, located in the Snoqualmie National Forest, is a large reservoir that provides water and electrical power to residents of Everett and Snohomish County.