In case this is helpful information, I passed down the 99 switchbacks (plus or minus a few) on 7/21. If my memory serves me correctly (which it sometimes doesn't at altitude), the top switchback leg had the worst & most precarious snow crossings. Here are a few pictures of them:
I would be very careful crossing them. Many of the switchbacks had snow crossings, but it was the ones near the top that were the worst. The trail above Trail Crest was pretty clear except for a large snow field crossing near the summit. Pictures of that here:
