The reason I ask specifically about these areas, is I also understand them to be generally 'famously stable', but with lots of small sections of much higher hazard. Again, just wondering what the conditions were when slides occurred, ie early season with a warm bed surface, and huge warm snowfalls, unconsolidated, with lots of wind, perhaps.
The 13 ft. slab incident, garyabrill, are you aware of any other details? Would there be an incident report recorded? If not, thanks for the reply so far.
George
I'll answer the last one first, george. The 13' slab happened on about February 5th of 1990 - the same day as the avalanche path off Mt. Snoqualmie into Alpental's lot and probably the same day as the slide that is visible on 20 beneath Ruby Mtn. There was as much as 500" of snowfall in 3-1/2 weeks at Baker. On about the 5th, the snow level rose to 4500' and all of these slides, and some even bigger came down. The largest crown I saw was near 25' on the upper Mazama Gl on Baker.
I think it is generally true that dry snow that falls steadily at Baker in the mid and upper 20's tends to stabilize fairly rapidly if the snowfall rates don't get too high and if you don't get too much wind, wide freezing level swings, or prolonged clear periods between storms.
Recall the fatal slab at Baker in 1999 was 13' deep but is thought to have been skier triggered.
I'd say the terrain at Baker tends to be quite steep and convex, and is loaded by southerly winds near Austin and Blueberry, so you've got to take that into account over the long run. If the hazard is Considerable or higher or moderate with bad layers, it is probably a game of roulette to ski the very steep convexities near those slopes over the long run.
If you want to look up a little information regarding decisionmaking, google "ATES - Avalanche Terrain Exposure Scale" and "Avaluator" to see the thinking and processes that were involved in the CAA's creating these new tools. I actually suggested a similar approach to Burgdorfer when he wrote the first edition of his book around 1983 or so. I've taught in a similar fashion since then, but of course didn't have the statistics to justify the risk matrix or to map out the terrain. But the way the terrain was mapped by the CAA in the ADFAR program, of which the ATES is a component was not by Google, but by having (I recall) about 30 guides come to a consensus on defining the terrain part of the risk equation. Nonetheless, in talking to some of the folks who were principal in working on this valuable project, it was said and makes sense that (as in avalanche forecast hazard levels) most experienced guides (and I would assume experienced recreationalists as well) would probably have a very similar analysis of the terrain for any given tour). Although this method was designed for newbies, it really replicates the process that guides would use in the planning phase of choosing a destination. That was confirmed to me by a couple of the folks who worked on ADFAR. I won't name names because I would want to ask their permission before I'd want to do that.
Anyway, I am sure that most would agree that the terrain north of the divide from Austin to Table and Hermit Saddle would be rated either "Complex" or "Challenging", and probably the most of it the former.
