Actually, the Mammoth Lakes area is the site of an ancient volcano with a quite large caldera (think of it as an "almost supervolcano"). If we get an eruption of this volcano again we may be talking the possibility of more volcanic ash spewed into the atmosphere than the Mt. Tambora eruption back in 1815 (Tambora spewed out 15
cubic miles of ash), but it won't be anywhere close to the potential amount of ash from an eruption of the
supervolcano in Yellowstone National Park; scientists have estimated that the last Yellowstone eruption spewed some
50 cubic miles of volcanic ash into the atmosphere.
