May 21, 2012 at 12:28 PM ET
Updated May 23, 8:40 a.m. ET -- Four climbers died while descending from the summit of Mount Everest last weekend.
Three other climbers are said to be missing and feared dead, according to NBC News' Miguel Almaguer.
Eberhard Schaaf, 61, from Aachen, Germany, who was climbing with the Eco Everest Expedition to remove decades-old garbage from the mountain, died on Saturday along the normal Southeast Ridge Route on the 29,035-foot peak.
Shriya Shah, a 32-year-old Nepal-born woman living in Canada, and a Korean, Song Won-Bin, also died while climbing down from the summit at the weekend, Tourism Ministry official Gyanendra Shrestha said.
"Schaaf died at the South Summit of Sagarmatha due to altitude sickness," said Ang Tshering Sherpa, chief of the Asian Trekking company that organized the expedition, referring to the Nepali name of the mountain. South Summit is about 28,697 feet high.
"If the family wants the body to be brought down we will try, but it is very difficult to do so from that altitude," Sherpa said.
Over the weekend, a 73-year-old Japanese woman improved her own record and climbed the peak for a second time at the weekend becoming the world's oldest woman to scale the giant peak.
Two Sherpas have died so far this season -- one after falling into a crevasse and the other reportedly from altitude sickness, according to National Geographic magazine. At least 236 people have died climbing Everest since 1950.
The deaths mark an already controversial season on Everest. On May 5, Himalayan Experience announced that it was canceling its expedition because of safety concerns. Minimal snowpack and warm temperatures, among other factors, had led to dangerous conditions, including rock fall and avalanches, the company said.
Michael Fagin, who provides forecasting services for Everest teams and runs everestweather.com from Redmond, Wash., said the spring had been very dry and windy. In the past week, winds had reached up to 80 mph; climbers on Everest prefer them under 30 mph.
Eric Simonson, Himalayan program director of International Mountain Guides, told msnbc.com last week that to cancel an Everest expedition so early was "quite unprecedented," but added it is unreasonable to expect every team to agree on how to handle difficult conditions.
"They’re betting on there being a problem and all the other expeditions that have stayed are betting on our ability to mitigate that problem. I don’t think it has to reflect poorly on anyone."
Last week, the National Geographic-North Face expedition, led by accomplished mountaineer Conrad Anker, canceled its plans to summit via the West Ridge due to icy conditions, but will still attempt to reach the peak via a different route.
About 300 climbers remain on the mountain at different camps waiting for a window of good weather to try to climb the peak before the onset of annual monsoon rains next month, which effectively ends the climbing season in the Himalayas.
Reuters contributed to this report.
Rebecca Ruiz is a reporter at msnbc.com. Follow her on Twitter here.
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