Dec 16th, Kelso Mountain Avalanche - questions

[the_hare]

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[14ercooper]

Those are actually really cool (and are quite a bit easier to understand than the giant wall of numbers I gave!), and looking over them, it does look like you matched them to the numbers I got to within the margin-of-rounding. Information (and especially easy-to-understand information) is something I'm always a huge fan of!

[ekalina]

This is excellent. Thanks for doing this work, 14ercooper and the_hare. Beggars shouldn't be choosers, but if you wanted...

I am curious about accounting for the number of forecasts at a certain danger rating in the results (since normalizing by the number of people subject to avy danger at each danger rating is mostly unknowable). For example, on average we should expect X number of accidents per 100 moderate danger days, but Y number of accidents per 100 considerable danger days. Is this something that would be useful to know, and possible to calculate with the current data?

[cottonmountaineering]

cool visuals! i wonder why E aspect is way overrepresented, garbage data or something else?

[SkaredShtles]

cool visuals! i wonder why E aspect is way overrepresented, garbage data or something else?

Prevailing winds W->E results in major windloading on east facing slopes.

[cottonmountaineering]

cool visuals! i wonder why E aspect is way overrepresented, garbage data or something else?

Prevailing winds W->E results in major windloading on east facing slopes.

Could have sworn the general prevailing winds are from NW->SE and not so much W to E, in the front range the prevailing winds are N to S

[14ercooper]

This is excellent. Thanks for doing this work, 14ercooper and the_hare. Beggars shouldn't be choosers, but if you wanted...

I am curious about accounting for the number of forecasts at a certain danger rating in the results (since normalizing by the number of people subject to avy danger at each danger rating is mostly unknowable). For example, on average we should expect X number of accidents per 100 moderate danger days, but Y number of accidents per 100 considerable danger days. Is this something that would be useful to know, and possible to calculate with the current data?

I can take a look at running these numbers a bit later today, since that's also seems pretty interesting to me now that you've mentioned it, and I just hadn't thought about grouping it like that before. I think I have enough data to calculate that.

cool visuals! i wonder why E aspect is way overrepresented, garbage data or something else?

I suspect it's a combination of wind loading (the data's taken over the entire state of CO, and I do see a lot of storms blow generally W->E) as well as sun heating effects.

[Jorts]

cool visuals! i wonder why E aspect is way overrepresented, garbage data or something else?

Prevailing winds W->E results in major windloading on east facing slopes.

Could have sworn the general prevailing winds are from NW->SE and not so much W to E, in the front range the prevailing winds are N to S

Depends where you are in the state. In the SJs we get more SW wind. Regardless prevailing wind has a westerly element. In addition to deeper, skiable snow because of prevailing winds, east aspects are also shady in the afternoons when it's warmer outside so there's less meltfreeze cycling and more facet preservation/growth than found on warm, sunny aspects.

It'd be interesting to know accident rates per capita. As in x # of accidents per y # of skier hours. I bet there are more skiers out there in the backcountry than the other user groups.

[Roca]

This slope has proven to be a repeat offender. Basing your decision to cross this slope on the details of the forecast is playing with fire.

Yes spreading out is a good idea but hikers and even experienced skiers just don't do this well especially when trail needs breaking. In the famous 2013 Sheep Creek avalanche the skiers spread out 50' apart...obviously not enough. It's hard to gage how an large an avalanche on a slope like Kelso will be and how far it will propagate. And what if the group does spread out correctly and one person gets caught only to get killed by trauma? Or buried under 8' of snow? Again, playing with fire.

IMO the best way to deal with this slope is to avoid it altogether-- ie give it a wide berth. It's unfortunate that the trail happens to be on an old mining road that works great in the summer but is dangerously exposed in the winter. And it's also unfortunate that leaving the trail to avoid this slope is very inconvenient because of the willows.

So here's the hypothetical situation: A group is hiking up the trail. They looked at the avy forecast and interpreted that things aren't too dangerous. Unknown to them, and thanks to the NW flow, the 2" of snow at the trailhead is actually a 10' wind slab up on this Kelso slope that is now cooking in the sun. They are cruising up the well packed trail and get to the soon-to-to-be-placed sign that says something like "hey sorry the trail passes under this dangerous slope - get educated and make your own decision". They weigh their options. Should they leave the trail and head off to posthole in the willows and avoid this slope, or continue up the beaten trail?

Point is that part of avy education is avoiding slopes like this, which is what the trail does not do. I'm pretty sure people are gonna follow the trail.

[SkaredShtles]

<snip>
Yes spreading out is a good idea but hikers and even experienced skiers just don't do this well especially when trail needs breaking. In the famous 2013 Sheep Creek avalanche the skiers spread out 50' apart...obviously not enough. It's hard to gage how an large an avalanche on a slope like Kelso will be and how far it will propagate. And what if the group does spread out correctly and one person gets caught only to get killed by trauma? Or buried under 8' of snow? Again, playing with fire.

IMO the best way to deal with this slope is to avoid it altogether-- ie give it a wide berth.

Absolutely - first option should *always* be avoid a slope if suspect. But someone mentioned what to do if a suspect slope was *unavoidable* - in which case, crossing one at a time should be a standard operating procedure.

And yes, it gets somewhat cumbersome with larger groups, but IME, one shouldn't toss out easy safety measures for expediency.

[justiner]

THANK YOU: convenience over safety is negligence.

I don't agree that traveling in avy terrain should be done on autopilot. "Oh but the summer trail led us right to the slope,?" is a poor excuse. You see how, "Oh but there was no sign to tell us exactly of the dangers" also falls into that bucket? "spreading out makes breaking the trail in front of me hard", etc, etc, etc. This is all denial of the present situation in front of you. Many times humans get away with this and in our modern lives filled with convenience it happens all the time without us noticing.

By no means am I trying to talk down to anyone, but maybe the experience one is looking for is uphill access at a ski resort. I take avalanche terrain very, very seriously, my understanding of the dangers is also high (just read the CAIC site!), and my education on how to interpret local conditions is very low. If I take all that into consideration, I am a danger to myself on suspect slopes.

If there is an unavoidable slope in front of you -- remember back to the basics of how accidents happen in the backcountry: a series of small mistakes in judgement compounding. Perhaps traveling to that spot was a mistake. Perhaps not having the proper avy training was another. You're now up to two mistakes in the series. Maybe a third is one did not check the avy forecast, or one member in your party disagrees on what to do to handle the terrain. Chances are now in the favor of an accident.

[SkaredShtles]

THANK YOU: convenience over safety is negligence.

I don't agree that traveling in avy terrain should be done on autopilot. "Oh but the summer trail led us right to the slope,?" is a poor excuse. You see how, "Oh but there was no sign to tell us exactly of the dangers" also falls into that bucket? "spreading out makes breaking the trail in front of me hard", etc, etc, etc. This is all denial of the present situation in front of you. Many times humans get away with this and in our modern lives filled with convenience it happens all the time without us noticing.

By no means am I trying to talk down to anyone, but maybe the experience one is looking for is uphill access at a ski resort. I take avalanche terrain very, very seriously, my understanding of the dangers is also high (just read the CAIC site!), and my education on how to interpret local conditions is very low. If I take all that into consideration, I am a danger to myself on suspect slopes.

If there is an unavoidable slope in front of you -- remember back to the basics of how accidents happen in the backcountry: a series of small mistakes in judgement compounding. Perhaps traveling to that spot was a mistake. Perhaps not having the proper avy training was another. You're now up to two mistakes in the series. Maybe a third is one did not check the avy forecast, or one member in your party disagrees on what to do to handle the terrain. Chances are now in the favor of an accident.

Another important thing to note when you're involved in partner/group travel - have a conversation BEFORE departing for your objective with said group about how you (as a group) are going to handle decision-making in avalanche terrain. And continue to have conversations about conditions as you go. Don't defer if you have concerns. Make them known.