How do you mange or minimise risk if you have to travel on these aspects or choose to ski them? Well you don't manage the risk with any degree of certainty as you just don't know for sure where weak spots are, and you will for sure not know the true propagation risk from a trigger. You can't minimise what you don't know - so uncertainty! And yet graphically on the above for the inexperienced person there is a temptation to look at these localized hot spots in the rose and think "I can avoid them", as surely I will recognize these weak areas and can ski/walk/climb around them.
Black 100% chance of getting whacked while either minding your own business in Galtur or being suicidal in Tignes
Red 98% chance of getting whacked on an aspect with that high level of risk and the Scottish equivalent of Black sometimes(apart from Gaick Lodge our main roads and villages are not in avalanche runout zones so Black does not apply)
Orange the big problem (to me) be it slices of tray bake sized considerable, or isolated hot spot. If the rose is all orange then in my view its just the same as red but less obvious. You have a very high chance of getting whacked. Stick some localised Orange risk in among yellow then it becomes 50/50 and that's still scary uncertainty as folk think they can recognize the danger hot spots and avoid them. Maybe they can, but then maybe not. A low angled slope day for me, well away from run out areas.
Yellow maybe a 40% of getting away with it, but victim triggered death is still very likely if you hit a hot spot and it propogates into something big or is above a terrain trap.
Green well either its the best of Scottish neve and you should be climbing with blue skies, or get the lawn mower out in February. If its the best of Scottish neve and its a sunless aspect then watch out as next time it snows as there's bound to be something growing on the top surface that will give a high risk when it snows next.
Having a blue bird day, or up for it then the glass half full person will go for it. Sadly they might end up with the glass all empty and smashed. It's a bit of a gamble and the more times you roll the dice the more chance you won't be needing your old age pension. 50/50 isn't odds, its worse than Russian Roulette!
Piss or get off the pot
The above americansim is pretty appropriate. Only one thing is for sure, we can only manage uncertainty up to a point. We live in a chaotic universe, bad things happen to good people and as mountain folks a lot of good things happen to good people as a reward for getting out there. I think we have to accept that the line between the best day skiing of your life and geting taken out is pretty close if you really want the powder days. If you dont accept that then take up another sport. We can reduce risk by managing uncertainty and reduce consequences by equipment and terrain choices, but in the end avalanche prediction and avoidance will never be 100% accurate. I am told knitting is pretty safe if you prefer a more sedate pastime with easier risk assessment.
Avalanche Types and Uncertainty
Some types of avalanche are more predictable i.e "certain" and some less so and some types of avalanche risk can be more easily seen in tests and observations. The ones that concern us the most are of course the least predictable with the greatest uncertainty so require extreme caution due to uncertainty. You might think Windslab/Stormslab the one that kills the most folk should be "Extra Caution". But, if you think about it you can work out in advance the Aspects that might be affected from a weather forecast, and very importantly observed wind direction, Angle of slope based on contours, preciptation type and deposition based on Altitude, and what the slope is Anchored to based on summer knowledge of your ski patrol/local area, or previous avalanche forecasts that mention temperature rises and surface or deeper instabilities.
|Wet snow release triggering a weakly anchored slope|
|Think: Angle, Aspect, Altitude, Anchors and Avoid|
|Powerful wet snow glide avalanche that takes everyting in its path. BEM above Laganbarbh|
|Persistant slab, skier triggered March 30th 2013 Glencoe|