For nearly two weeks, the nation has been transfixed by wildfire spreading through Yosemite National Park, threatening to pollute San Francisco’s water supply and destroy some of America’s most cherished landscapes. As terrible as the Rim Fire seems, though, the question of its long-term effects, and whether in some ways it could actually be ecologically beneficial, is a complicated one.
Some parts of Yosemite may be radically altered, entering entire new ecological states. Yet others may be restored to historical conditions that prevailed for thousands of years from the last Ice Age’s end until the 19th century, when short-sighted fire management disrupted natural fire cycles and transformed the landscape.
Read more. [Image: NASA Earth Observatory]
Mapping firm Esri has today released an interactive map of the California Rim Fire, which is now in its 12th day. In the map above, you can explore the fire’s geography — its invasion of Yosemite National Park, its encroachment upon the Hetch Hetchy reservoir which supplies the Bay Area’s water supply, and its proximity to a cluster of Toulumne county communities, many of which are under evacuation orders.
For the past 10 days, firefighters in California have been struggling to contain the Rim Fire, now one of the largest in the state’s history, as it blazes across the Stanislaus National Forest and into Yosemite National Park. As of last night, the Rim Fire had burned nearly 240 square miles, disrupted hydroelectric power supply to San Francisco, and destroyed 23 structures. The fire is only 15 percent contained and still threatens thousands of homes in the mountainous region.
Moonwalk by Bryan Smith is part of a National Geographic Channel series called The Man Who Can Fly. This particular scene features Dean Potter, a record-breaking climber who lives in Yosemite, walking on a highline between two enormous granite rocks.
To the eyes of a seven-year-old, Upper Yosemite Falls appears to materialize inexplicably from the top of this 1,400-foot cliff. So I explain to Alex that up there, beyond sight, a lot of melting snow fills that creek with water. But I don’t try to explain, yet, that Yosemite Creek, like many High Sierra streams, is ephemeral—this creek and waterfall dry up by July or August every summer. A rare heavy rain in autumn may temporarily resuscitate the creek. It alternately trickles and freezes through winter. But as spring liquefies the prodigious high-country snowpack, a rejuvenated Yosemite Creek bulks up again, building to a crescendo in May and June.
Nor can I figure out, at the moment, how to describe for her one certain outcome of a warming climate: less snow in Yosemite’s future. Snowfall has declined measurably for decades in virtually all parts of the world that receive it. In the Sierra, as across the Mountain West, snow melts out and streams reach peak runoff two to four weeks earlier than a half century ago. The upshot is that this waterfall and every other one in Yosemite will reach peak runoff weeks or months earlier in the year by the time Alex is grown up. The profound effects of this seasonal shift in water flows will reverberate throughout ecosystems across the western United States, the region that’s home to many of our big wilderness parks.
Seeing and hearing the upper falls, it’s hard to believe it dries up every summer. I remember a late-summer day years ago, when I looked toward Yosemite Falls and it wasn’t there. For an instant, I assumed I must have been looking in the wrong spot, but I wasn’t.
Read more. [Image: docentjoyce/Flickr]