4 climbers die on Everest, 2 Colorado climbers OK

Tom Burton and Will Calton, both of Ogden, had already completed their descent from the summit when three climbers in a different group died and two went missing. According to media reports, one of those missing climbers, a Chinese woman, was later found dead.

Burton's wife, Gaylynn, said her husband was healthy but that Calton suffered an injury in an accident.

She said Calton spent the night in the hospital for observation after he suffered two broken ribs and a concussion while climbing down from Mount Everest's summit.

"We expect a full recovery," she said. The other members of their climbing party, Team Leader Jeff Reynolds, of Santa Fe, N.M., and Rob Cassady, from Colorado, are also safe.

Another Coloradan, Dr. Jon Kedrowski, of Avon, told Denver's Fox 31 TV station that he was unable to reach the summit due to severe weather. He said he tried to help some sickened climbers. He may make another summit attempt this weekend, according to his blog.

The Utah team reached the summit Saturday night (U.S. time), said Rex Baxter, Burton's brother-in-law. The family has been in contact with the pair and is in constant communication with a Sherpa at base camp. Calton and Burton last contacted the family as they traveled back down from Camp 4 to Camp 3.

"My guess is that they've reached Camp 2 by now," Baxter said Monday evening. Before reaching the summit, Burton and Calton's team had some weather delays.

The first clear weather conditions of the spring climbing season came Friday and Saturday, but a windstorm swept the higher altitudes of the mountain by Saturday afternoon, said Gyanendra Shrestha, of Nepal's Mountaineering Department.

An estimated 150 climbers reached the summit on either day, most of them on Saturday.

"There was a traffic jam on the mountain on Saturday. Climbers were still heading to the summit as late as 2:30 p.m., which is quite dangerous," Shrestha said by telephone from Everest's base camp.

Climbers are advised to not attempt to reach the summit after 11 a.m. The area above the last camp at South Col is nicknamed the "death zone" because of the steep icy slope, treacherous conditions and low oxygen level.

"With the traffic jam, climbers had a longer wait for their chance to go up the trail and spent too much time at higher altitude," Shrestha said. "Many of them are believed to be carrying a limited amount of oxygen, not anticipating the extra time spent."

The four climbers who died Saturday were believed to have suffered exhaustion and altitude sickness.

They were identified as Eberhard Schaaf, a 61-year-old German doctor; Shriya Shah, a 33-year-old Canadian resident who was born in Nepal; mountaineer Song Wonbin, a 44-year-old South Korean man; and Chinese climber Ha Wenyi, 55.

The missing climber is a Nepalese Sherpa guide.

Weather conditions are clear enough to permit climbing to Everest's 29,035-foot peak for only a short time in May.

On May 10, 1996, eight people died on what is believed to be the worst day on Everest. The main reason was said to be that climbers who started their ascents late in the day were caught in a snowstorm that swept the mountain in the afternoon.

Barring no delays in flights out of Nepal, Burton and Calton expect to return to their wives and children around June 1.

The Associated Press contributed to this article.