Yes it certainly is erratic. For those not familiar with Baldy, here are the snowfall totals for 2006 - 2013 (largest storm totals in parentheses) (with some El Nino/La Nina data added just for fun):
2006: 170" (24") --weak El Nino
2007: 9" (3")--moderate La Nina
2008: 222" (30")--weak La Nina
2009: 128" (18")--moderate El Nino
2010: 318" (48")--strong La Nina
2011: 181" (48")--weak La Nina
2012: 78" (18")
2013: 40" (11")
So based on the above, while we could see a repeat of the past two years, overall you've about a 50% chance of having several good ski days at Baldy on any given winter. Given how much nicer it is to do the 1:20 drive from LA to Baldy than the 1:45 drive to Mtn. High or the 2:30 drive to Big Bear/Snow Summit, and given how much better Baldy's terrain is, $59 seems like a reasonable risk. YCMV (your calculation may vary :) ).
Or if you'd prefer a more formal calculation:
Let suppose there's a 50% chance it's a bad snow year, in which case you'd do 0 ski days, and a 50% chance it's good, in which case you'd do, say, 6 ski days. Further, let's use their full day pass price of $50. And let's suppose you use this strategy every year.
Then, if you don't buy a pass, your average layout per year would be .5 * 0 + .5 * (6* $50) == $150 (i.e., $300 on the good snow years, and $0 on the bad years).
So that means that any year you can instead buy a pass for under $150 you should, since that's a superior strategy. If you'd ski more days on good years, the cutoff goes up; if less, it goes down; likewise, if you can get discounted day passes, that also reduces the cutoff price you should be willing to pay.
Edited by chemist - 12/19/13 at 7:31pm