LAS VEGAS, July 15 (UPI) -- Two volunteer teams say they will search the California-Nevada border area for any signs of adventurer Steve Fossett, missing with his plane since September.

One group of volunteers set out this week to look around in remote forests and canyons where the high-profile adventurer's small plane is believed to have crashed. The second plans to conduct its search next month.

The New York Times (NYSE:NYT) said Tuesday that the two teams are both led by members of the Explorers Club, of which Fossett was also a member.

The leader of the August search team, Washington investor Robert Hyman, told the newspaper that the expedition will also seek to determine why a massive search-and-rescue effort failed to turn up any sign of Fossett after he went missing.

"We just want to find Steve, and we want to help with the methodology with search and rescue," Hyman said.

The missing Fossett was declared legally dead Feb. 15.