Rescue crews have narrowed the area they're searching in the rugged Cascade foothills for a skydiver who vanished during a jump.

King County sheriff's Sgt. Cindi West says they made the decision based on the flight pattern of the helicopter he jumped from and information from his cell phone.

There's been no sign of Kurt Ruppert since he jumped out of a helicopter at 6,500 feet on Thursday afternoon. The 29-year-old from Lake City, Fla., was wearing a special wing suit with fabric under the arms to allow him to glide like a flying squirrel.

Searchers were hoping Ruppert was stuck in a tree with his parachute or perhaps lost in state-owned land around 4,200-foot Mount Si.

He was skydiving with two friends, and they were taking turns jumping. The friends were waiting at a grassy landing area, but neither saw whether Ruppert's chute deployed.