Alaska State Troopers say the Alaska Army National Guardsman missing on a hike last week hasn't been found, with his family and friends describing him Monday as an accomplished outdoorsman and a rugged individualist.

Both air and ground searches were in progress Monday morning after Sunday efforts failed to find 26-year-old Spc. Nephi Soper, according to a Monday email from troopers spokeswoman Beth Ipsen. Troopers' Helo-2, as well as a Guard helicopter, were searching for Soper as weather that grounded them for much of Sunday lifted.

Soper, assigned to the Alaska Guard's 1-297th Reconnaissance and Surveillance Battalion, missed a 6 p.m. Friday drill formation on Joint Base Elmendorf-Richardson after a taxicab dropped him off for his solo trek Thursday night at the Prospect Heights trailhead on the Anchorage Hillside. His plans reportedly involved traveling north overnight, emerging near Arctic Valley Road and proceeding to JBER.

Ipsen said the Guard also planned to fly a team of pararescuemen to Long Lake, where they were set to travel along Soper's planned course.

"They'll ski the anticipated route back to the North Fork Camp Creek trail," Ipsen wrote. "Ground teams are in the Arctic Valley Road and Lower Ship Creek Valley (areas)."

Ipsen said at least 30 people were coordinating and conducting Monday's search, including troopers, guardsmen and Alaska State Parks employees as well as volunteers and search dogs with the Alaska Mountain Rescue Group, the Nordic Ski Patrol, MatSAR and Alaska Search and Rescue Dogs.

Ground searchers were being deployed with caution, Ipsen said, after the weekend's heavy snowfall across the Southcentral region.

"There has been a recent accumulation of snow and the higher areas need to be assessed for hazards before they send in ground searchers," Ipsen wrote. "Searcher safety is the priority here."

Lt. Col. Candis Olmstead, a spokeswoman for the Alaska National Guard, said in a Monday email that nearly 20 guardsmen were committed to the search, including the Pave Hawk helicopter crew making the Long Lake flight and half a dozen pararescuemen. She said Guard helicopters had been searching for Soper since Friday, due to his reputation for punctuality and his advance word that he would be hiking to Friday's drill formation.

"Spc. Soper is a solid soldier," Olmstead wrote. "His supervisor and co-workers have stated that he is always in the right place and the right time with the proper equipment. He is on-time, reliable, hard-charging and physically fit."

Ken Soper, Nephi Soper's father, said his own service with the Army led him to encourage his children to also join the military. He recalled urging them to accompany him on long hikes as they grew up in Missouri, including at least one Ken called a "road march."

"I'd talk them into going on a 19-mile road hike from Oak Grove to Independence," Ken Soper said, laughing. "We only made it halfway."

Ken said Nephi liked spending quiet time by himself in the outdoors.

"He likes hiking out into the back(country) and climbing mountains and all that stuff," Ken Soper said.

The two went on a number of father-and-son hikes, including one into the Florida backwoods that Ken said was reminiscent of the Costa Rican jungle in the film "Jurassic Park."

"Me and him have done a lot of investigative hiking," Ken Soper said. "Sometimes we'd go out on a full moon to go on some night hiking courses and see what kind of wild animals we could see."

Cheryl Lockett Alexander, who now lives in Kentucky but worked with Soper at the Wal-Mart store in Midtown Anchorage, said he was "a real loner."

"When he went out, he went out alone -- he did everything alone, he never associated with anyone," Alexander said. "He'd just smoke on the side of the building at break time; he'd never hang out in the breakroom."

Alexander said she bonded with Soper over his military service because her husband served in the Army and her son is in the Navy. She soon learned that Soper liked to make long-distance walks across Anchorage.

"I used to feed him all the time; he looked so skinny all the time," Alexander said. "He walked from one end of Anchorage to the other, and I told him he needed to get a bicycle -- and when he got a bicycle, he went even further."

The one area of life where Soper opened up, Alexander said, was in his nature photography of Alaska plants and scenery, including a few colorful examples posted on his Facebook page.

"The weather, no matter what it was, never stopped him," Alexander said. "When he went into the mountains, he thought he was invincible."

The Guard previously reported that Nephi had been carrying a three-day pack. Ipsen said Monday that he purchased food at a Holiday convenience store, where he was recorded on a surveillance video wearing an outdated desert-camouflage jacket and black pants shortly before his disappearance Thursday.

Ken Soper said he hadn't heard much about the search beyond media reports Monday, save that troopers had told him Nephi wasn't carrying a rifle when he was last seen Thursday but may have had a .38 handgun.

"I always reminded him to bring some kind of firearm for the dangerous stuff," Ken Soper said.

Alexander, Nephi's friend, said she was still trying to imagine the best outcome for the search Monday.

"I'm hoping he's in some cave somewhere," Alexander said.

Troopers are asking anyone with word on Nephi Soper's whereabouts to call 907-262-4453.