Why Does Everyone Climb Everest At The Same Time?
J Thoendell stashed this in Misc
Everest is always formidable but for most of the year, it is also un-climbable. The monsoon season from June through September brings drenching rains down low and heavy snow up high. Conditions dry out in October, and some climbers choose to make a summit push then, but by late fall, short days and frigid temperatures increase the difficulty of climbing.
The majority of expeditions arrive at Base Camp in April, when temperatures warm up enough to make climbing possible. Then, all eyes turn to the jet stream.
Only when the jet stream shifts far enough to the north do winds calm down to a more reasonable range of 10 to 20 miles per hour, Fagin said. When he forecasts for the mountain, he compares six weather models, blends them together and puts the most faith in the models that appear to be the most accurate at the time. He also factors in real-time feedback from clients on the mountain.
Fagin recommends climbing only when there is a good chance that the jet stream will stay far enough to the north for at least five days in a row -- long enough for teams to get from Base Camp to the summit.
Most seasons get an average of 12 summit-worthy days, said Alan Arnette, a mountaineer and respected Everest blogger based in Fort Collins, Colo. But during the spring of 2012, there were just five good days for summiting and 500 people on the mountain, leading to dangerous crowds and notorious images showing long lines on the way up.