Witnesses said they saw the unidentified man scaling the Seattle City Light tower early Friday and then saw a bright flash of light and an explosion, The Seattle Times reported Saturday.
City Light spokesman Peter Clarke told the newspaper that would be consistent with a short-circuit of a high-tension line.
A Snohomish County Sheriff's Office helicopter was brought in for an aerial survey of the situation and it was determined the man was dead.
The utility cut power to the circuit so a Seattle Fire Department Technical Rescue Team could recover the body. Power was rerouted during the operation, leaving only one house without power, the Times said.
Authorities were investigating how the man gained access to the tower.