Brian and I weren't sure we would be able to pull this off with the weather turning and it being so late in the season, but we got a one day window and went for it. We started at Park Headquarters/TH for Laguna Toro at 6:14am. Being late in the season, we ran the first two hours in the dark which was not as fast as we would have liked- especially in the forest with many downed trees and wet patches. We had a beautiful sunrise in the laguna basin with incredible fall colors and saw a few foxes. Although we carried the mandatory harness and steel carabiner requirements for the tyrolean traverses, we bypassed the first by running across the delta at the end of Laguna Toro as the water levels were low. We lost some time navigating around the glacier and the braided trail system in the moraine (we did this as an onsight) but eventually climbed up to the main trail above and to the windy pass. Wind speeds were actually quite low during the day and didn’t pick up until the end of the run. We only saw three other parties the entire day- again, late season. We carried small soft flasks with filters as water was generally plentiful although I would recommend avoiding most of the streams in the cattle grazing zones. The portion of trail that dropped off after Huemul Pass was a mess- incredibly steep and loose even with the fixed ropes. Unsure how much longer this section is sustainable. Seems so eroded. The wind speed picked up drastically as we rounded the circuit towards El Chalten. We had been keeping a decent clip up until but the final miles turned into a headwind slog. We ran the final portion along the highway and ended back at the headquarters/TH 11hrs 29 min and 46 seconds after starting. Celebrated with steaks, ice cream and in proper Argentinian style, fernet and coke.