GRAND TETON NATIONAL PARK, Wyo. -

A Minnesota man suffered life-threatening injuries Friday morning after an apparent fall while attempting to make a solo summit of Grant Teton.

Park rangers say they successfully rescued Steve Markusen, of Minneapolis, Minnesota, after dense clouds and inclement weather hindered a quicker rescue. Markusen was free climbing alone without a climbing harness, rope or helmet. He reached 13,300 feet, and fell between the Friction Pitch and V-'itch on the upper Exum Ridge route.

Markusen doesn't remember what happened, but he thinks he may have been hit by a rock, which caused the 100-foot tumble.

Two climbers without cellphones found Markusen, so they located other climbers with a cellphone and called the Jenny Lake Ranger Station. Two more parties, including four firefighters from Boston, came upon Markusen and provided first aid.

Cloud cover hindered visibility, so the Teton Interagency contract helicopter flew seven park rangers and a Teton Interagency helitack crew member to the Lower Saddle of the Grand Teton (elevation 11,600 feet), which was below the thick clouds. From there, park rangers tended to Markusen's injuries.

Together the three rangers prepared Markusen for a short-haul flight off the mountain and he was flown to the Jenny Lake Rescue Cache at Lupine Meadows on the valley floor for transport to a medical facility. Park rangers said emergency medical technicians and paramedics set up a temporary emergency room inside the Jenny Lake Rescue Cache to stabilize Markusen before transporting him by park ambulance to St. John's Medical Center in Jackson, Wyoming. Markusen arrived at the local hospital at 4:20 p.m., over five hours after his fall.

Park rangers strongly advise climbers to wear helmets and carry appropriate climbing gear whenever making a summit attempt. Rangers also advise against solo climbing because of the added risk in the event of an accident.