By Alex Dobuzinskis
(Reuters) - Rescuers scaled a steep Alaskan glacier on Tuesday, making slow but steady progress in their effort to reach two hikers stranded at a remote snow cave for four days, officials said.
Aircraft have failed to reach the pair because of snow storms and low cloud cover, which create hazardous "white-on-white" conditions, said Alaska Air National Guard spokesman Staff Sergeant Edward Eagerton.
"It's hard to differentiate between the ground and the sky," Eagerton said.
Christopher Hanna, 45, and Jennifer Neyman, 36, on Friday were dropped off by airplane on the Harding Icefield in the remote Kenai Mountains on the southern coast of Alaska for a day of hiking and skiing, according to the National Guard.
But their outing took a dangerous turn when the weather quickly worsened and their pilot was unable to land to pick them up, the National Guard said in a statement.
The hikers, both Alaska residents experienced with extreme weather, have stayed in touch with friends and emergency officials by using their cell phones and a satellite-based text messaging device.
After their tent came apart, they took cover in a snow cave on Bear Glacier at an elevation of 4,300 feet (1,311 meters), according to the National Guard.
On Monday, a team of four rescuers parachuted to a drop zone about 15 miles (24 km) from the hikers. By the end of the day they had scaled the side of the glacier to within 7 miles (11 km) of the hikers' camp.
A helicopter crew on Tuesday spotted the hikers' skis, and officials received a text message from the two saying they were in good shape. But poor weather again prevented the aircraft from landing at the site, according to the National Guard.
"The helicopter's trying to find a way," Eagerton said. "The guys on the ground are making their way - we're getting closer."
(Editing by Sara Catania and Alistair Bell)