Are there even avalanche forecasts for this area? This is a place that historically sees little to no avalanche activity year in and year out.
Not true for the SoCal mountains in general. When they get snow, they often get a lot of it at once. SoCal's 5% probability of 90+ inches snowfall in a winter month is as high as Aspen, Breckenridge, Copper or Telluride. Baldy has had several OB avalanche deaths over the years, and after many storms there is delay in opening terrain until the snow settles.
Mountain High is not as high or steep, and is more thickly forested. I've skied that Sawmill Canyon a few times myself, just as a means of returning to my car in the East parking lot from the top of West. With 2 of the deaths being patrollers, I'd certainly be more curious about the details. But I suspect it comes from one of the danger signs, Familiarity. These guys knew the terrain, knew that avalanche history was much more rare than on Baldy's more obvious exposures, and probably didn't test it adequately. Or it could have been $#!& happens, as when Mammoth bombed Wipe Out and Paranoid Dec. 21, and they still slid shortly after patrol opened them.