First: there was almost no one in this most popular backpacking spot. The LYV campground has dozens of people in it every night during the Half Dome season; it was a strange delight to experience it when completely empty.
Second: there were tiny frazil ice deposits in several places below Nevada and Vernal Falls, but in Emerald Pool the accumulation was up to 2 meters thick and covered 3/4 of the pool. These flows are remnants of the cold spell around New Years.
Third: last summer's Meadow Fire has completely changed the character of LYV, leaving it open and bare, but for black trunks. The campground area is unburned but a few minutes walk beyond there is a different landscape that's going to be a hot, sunny stretch in the summer, all the way up through Lost Valley.
Fourth: the little-known logjam in LYV has burned. This jam is upriver of the campground area, consists of several hundred tree trunks that have blocked the Merced River for many decades. It's big enough that it stayed in place during the flood of 1997. The jam is still there but the fire must surely have affected its stability.
Fifth: Consistent with the absence of people, there were none of summer's Steller's Jays in LYV.