"A tribunal of wizards go into a tent for four days, meditate, debate and look to the spiritual world for guidance. After four days, if white smoke emerges from the tent, the East Wall shall open." -anonymous, March 18, 2015
That was the best blog comment ever.
The answer is snow. We need enough snow to make the skiing good. Most of The Wall is a big talus field and it takes a lot of snow to cover the rocks. Usually when the base gets in the high 40's to mid 50's inch range, we open it. Additionally, we have to do enough avalanche mitigation work to substantially reduce the chance of avalanches occurring. That involves a lot of explosives work, ski scutting, ski packing, and other activities.
Sometimes continued warm weather, like the last few days, may cause a closure. As we get excessive water moving through the snowpack, wet slides are possible and we want The Wall closed when that happens.
Enjoy the photo I took on Little Lenawee Sunday afternoon.