Search efforts continued Sunday for a 26-year-old Alaska Army National Guardsman last seen nearly three days earlier, as he was embarking on a hike through the wilderness near Joint Base Elmendorf-Richardson.

Alaska National Guard spokeswoman Lt. Col. Candis Olmstead said in a statement late Saturday night that Spc. Nephi Soper, a member of the Alaska Guard's 1-297th Reconnaissance and Surveillance Battalion, left Thursday for what was supposed to be an overnight hike. A taxi dropped him off at the Prospect Heights Trailhead in Anchorage around 7 p.m. Thursday.

"He was equipped with a large backpack and was prepared to hike through the Campbell Creek and Ship Creek valleys," Olmstead wrote.

According to a Sunday email from Olmstead, Soper -- a guardsman since 2008 with time in the Missouri Army National Guard, who transferred to the Alaska Guard in 2013 -- had completed land navigation training during his time with the military, but members of his unit typically serve in teams and aren't expected to operate alone.

"Soper has not received additional/advanced survival training from the military," Olmstead wrote.

Olmstead said Soper had been slated to attend a drill formation Friday night on Fort Richardson, in uniform and carrying Army equipment kept in his locker at the armory. He is believed to have been carrying a three-day medium backpack when he embarked on his hike.

"He was expected at drill Friday evening at 6 p.m.," Olmstead wrote. "His equipment is in his locker currently."

Soldiers conducted an initial search for Soper Saturday, Olmstead said, with Alaska Army National Guard UH-60 Black Hawk helicopter crews on routine flights searching parts of the Chugach Mountains for Soper. Ground search crews were joined by Alaska Mountain Rescue Group (AMRG) members Saturday night.

"Alaska Army National Guard Soldiers searched Arctic Valley Road, scoped the mountainous terrain from high points, and hiked several areas seeking the missing soldier," Olmstead wrote.

Alaska State Trooper Rick Chambers said Sunday afternoon that weather conditions were preventing the deployment of air assets to search for Soper. Two of three ground search teams had been deployed Sunday to look for him.

"We have one team that is currently searching the Ship Creek Valley, from Arctic Valley Road into Ship Creek," Chambers said. "We have a second team that is searching the area of Near Point, and we have another team at the airfield that is waiting for weather to clear so they can be airlifted by helo to the area of Long Lake."

In addition to the AMRG support, Chambers said Alaska State Parks officials were searching the Indian Valley and Prospect Heights areas.

Although no sign of Soper had been found so far in Sunday's search, Chambers said the taxi driver who took Soper to Prospect Heights stopped at a Holiday gas station near Spenard Road and Minnesota Drive just after 7 p.m. Thursday.

The clerk recognized Soper, a frequent customer, and a surveillance video of the visit gave searchers a better look at Soper's clothing -- which was initially described as military-issue, but now appears to be a "chocolate-chip" desert-camouflage jacket dating back to the 1991 Persian Gulf War, with black pants.

"It looks like surplus gear," Chambers said.

Troopers also interviewed the taxi driver about Soper's backpack, but didn't learn anything further about what he was carrying.

Chambers said troopers hadn't discovered any indications that Soper's disappearance was intentional.

"We don't have any indication that he did anything else than what he intended to do, which was hike through the mountains and go to his training," Chambers said. "We think he's a guy that got lost."

At about 1 p.m. Sunday, roughly half a dozen vehicles -- including some with markings for AMRG and the Alaska Air National Guard's 176th Wing -- were parked at a staging area at the Ship Creek Valley trailhead along Arctic Valley Road. Weather in the area ranged from freezing rain at lower elevations to blowing snow at the staging area, higher up on Arctic Valley Road.

An Air Force radioman in a vehicle at the trailhead deferred further questions on the search to troopers and Olmstead. About a mile down a nearby trail, no searchers or helicopters were in sight, but the barking of dogs could be heard coming from areas downhill.

Anyone with information on Soper or his whereabouts is asked to call troopers at 907-262-4453.