I drove with Steve C from Fresno straight up to Horseshoe Meadows for an overnight acclimatization, and it worked like a charm. Overnight altitude did the job.
PS The weather was horrible everywhere in the mountains on Sunday. Snowed in Yosemite, hailed, lightning, too. It flashflooded in Tahoe & Reno (temps dropped 25 degrees instantly) It even rained in the central valley most of that night.
