Attempted to climb Mt Tyndall on 4/10/2019 from Shepherds Pass Trailhead (6300 ft).
Short end: the grade was too aggressive and abandoned at about 10,000 feet.
Notes: We were the only ones at the trailhead for two days. We saw one other pair of tracks a few days old with another set of ski tracks coming down. A badass person likely climbed to about 10K and skied down.
Heavy snowfall has covered the mountain with deep snow starting at about 7200 feet, starting off at the 15th switchback (There are 55 switchbacks in the first phase of the mountain). Note: I've climbed Williamson before and know the trail fairly well.
The climb is brutal from the getgo. You'll be climbing at about 100-110% grade right off the bat (1 hour in). In deep snow. You're going to need snowshoes (with a heel lift) because the snow will start to get softer at around noon and crampons for early morning climbing.
If you manage to summit and come down in the afternoon, expect the snow to get much softer and your cramponed feet to sink to your knee or thighs very frequently (and very frustrating).
Recommendation: unless you're in extremely good physical condition to be climbing at that grade for multiple miles, I recommend you wait until at least late May for the first phase of the climb to be snow free. It can be def be done, but it requires too much effort and one more day that we were willing to give.