The white substance that you see is not snow, instead it is merely sodium borate. Located in the middle of Peublo Valley, Borax Lake is a geothermally active area, with hotsprings in some places boiling at the surface, and geothermal reservoir temperatures of 335-400 degress F. Be aware that there are extremely high and fatal levels of arsenic in Borax Lake, so be careful not to drink the water. Unlike most lakes which sit at the low point on the valley floor, Borax Lake sits atop a mound that is 25 feet higher than the surrounding valley floor. This mound is an erosional remnant that held its ground while the surrounding landscape eroded. Core samples taken from this mound reveal that it is made of pure diatomite, formed mainly from the shells of microscopic algae called diatoms.
There is a rare breed of chub which lives in Borax Lake, the Borax Laek chub (Gils boraxobius) is directly dependant on the discharge of thermal fluids in Borax Lake. To hear an interesting story told by the Biology professor Lynn about what happened at Borax Lake when the chub got put on the endangered species act, click on the Real Audio link above to the right.