Lake 12021' in Evolution Basin from well below the top of Wallace Col, 6 hours later. I did not realize at the time how long it took to get over this col, but I knew it took a lot of time. I had to scout ahead, leave my pack at the top, and search out an easier route for my companion. The descent was not as steep, but even looser. We created mini avalanches of scree which raised choking clouds of dust. My advice; use Echo Col.