Mammoth Lakes sits at 8,000 feet on the east side of the Sierra, and the BLM flats down in Long Valley — around Crowley Lake and the hot springs — are the free-camp overflow. The catch is the inversion: on a clear winter night the cold air pools on that valley floor, which is how you wake up to minus eleven.
If you go
The dispersed BLM land down in the Long Valley basin near Crowley Lake, with its scattered hot springs, is a popular free camp near Mammoth — but winter inversions pool brutally cold air down on that valley floor, which is how we hit minus 11. The hot springs are a sensitive, heavily-loved resource, so tread light, pack everything out, and know that the cold down low can be far worse than up on the mountain.
