Sunday’s storm added a twist to this year’s fall color story. In my post from September 30th I waxed optimistic about the how the weather conditions—a warm September followed by a cold spell at the beginning of October—might lead to great fall color like we had in 2007. But there’s cold and there’s really cold. Scientists say that the best color comes from sunny days and cool, but not freezing, nights (see Wikipedia and The Buffalo Museum of Science). Temperatures definitely dropped below freezing all over the Sierra on Sunday, as the snow level was down to 5500 feet, and probably reached freezing each subsequent morning in most places above 5000 to 6000 feet.
What usually happens when a cold and windy storm blows through (like we had Sunday) is that trees that have already turned will drop their leaves, and some leaves that are starting to turn will wither and turn brown. I expect that’s already happened to many of the high-elevation aspens in the Eastern Sierra. The good news is that most of the lower-elevation aspens, and virtually all of the deciduous trees in Yosemite, were still green, and were probably unaffected by the storm. The cold weather should start all these trees turning quickly, but during the coming week or so there might not be much color anywhere, as trees that had turned will be bare or withered, and trees that were green will need a week or two to arrive at their peak color. But I’d guess we’ll see some good color among the lower-elevation aspens on the east side in one to two weeks, in the higher-elevation dogwoods in Yosemite (Tuolumne Grove and along Highways 41 and 120) also in one or two weeks, and in Yosemite Valley in two or three weeks. Barring further storms that is.
Since I haven’t been to the east side lately, I’d love to hear from anyone who has, especially if you’ve been there since Sunday and can tell us whether the those high-elevation aspens are bare or withered. Here’s one report from Dan Mitchell that seems to confirm my speculation that some of those upper-elevation trees are past prime.