The first time Kurt Ruppert jumped from a helicopter wearing a "wingsuit" above Washington's rugged Cascade Mountains, the jump went as planned.
The second time, he went missing.
About 130 trained mountain rescuers were to resume searching Sunday for Ruppert, 29, of Lake City, Florida, who was reported missing Thursday by two friends after he failed to show up at a landing zone in the mountains east of Seattle, authorities said.
"We don't know if he's on the ground. We don't know if his parachute deployed, and he's stuck up in a tree somewhere," Sgt. Cindy West, spokeswoman for the King County Sheriff's Office, said late Saturday.
"...It's going to be slow going."
Authorities and rescuers used the trajectory of the helicopter and cell phone signals from Ruppert's phone to narrow down the search area. Authorities did not say how it determined the cell phone signal, and it was not clear whether he attempted to use it or if authorities were able to track the signal another way.
The search was set to resume at 8 a.m. PT (11 a.m. ET), West said.
Authorities believe Ruppert jumped from an altitude of about 6,500 feet while wearing a special jumpsuit known as a "wingsuit," which allows a person to soar and glide before deploying a parachute.
Two friends, who shared the price of a helicopter rental with Ruppert, did not see whether his parachute opened on his second jump, authorities said.
Ruppert was not dressed for enduring Washington's cold overnight climate in the mountains.
"We still consider this a rescue mission," West said. "We realize that it is cold outside. But we are hoping he is alive and his parachute got stuck in a tree or something."
CNN's Chelsea J. Carter contributed to this report.