Nasty place to fly
Been back and forth over that area a lot of times in a Mooney. Never go below 15,500 though . Nasty terrain. Even the Mammoth lakes airport is notorious for DA related accidents.
Evil, evil Mt Wave on that side of the hills. Locals said there were towering cumulus that day as well. Lots going on that a single engine piston close to its service ceiling won't get you out of ... or even come close, if the ridge winds are over 25 knots.
Not too much like that in the UK to compare!