About 145 searchers combed the Mount Si area east of Seattle for 29-year-old Kurt Ruppert, who disappeared Thursday afternoon after he jumped out of a helicopter at 6,500 feet.
King County sheriff's Sgt. Cindi West said they looked specifically in a quarter-mile-square area near the summit, but kept searching other areas as well.
At the time of the jump, Ruppert, of Lake City, Fla., was wearing a special wing suit with fabric under the arms to allow him to glide like a flying squirrel. The suit is brown and green, and likely blends into the terrain, though his parachute was reportedly blue.
He was skydiving with two friends, and they were taking turns jumping from the helicopter. The friends were waiting at a grassy landing area, but no one saw whether Ruppert's chute deployed.
West said they made the decision to narrow the search area based on the flight pattern of the helicopter he jumped from and information from his cellphone's location just before the jump.
She expected the search to resume at dawn Sunday.
Searchers were hoping Ruppert was stuck in a tree with his parachute or perhaps lost in rugged state-owned land around 4,200-foot Mount Si, West said.
Ruppert has been skydiving seven or eight years and is good at handling a wing suit, said a friend, Art Shaffer, owner of Skydive Palatka in Palatka, Fla.
Shaffer jumped with Ruppert at midnight on New Year's Eve and said Ruppert left Tuesday to jump with friends in Washington.
Ruppert is not married and once owned a landscaping business, said Shaffer, who is in contact with Ruppert's family and friends.