Tracks on the slope indicate stability for certain avalanche problems?

[CirqueScaler]

I was touring alone today and came across a 38*ish slope w/ 15 or so tracks on it. In Utah today, our avalanche problems were new snow problems and wind slabs/loading.

I had committed to staying out of avalanche terrain while alone, but it made me wonder: do tracks on a slope indicate stability for certain avalanche problems such as loose dry, storm slabs, or wind slabs? Would riding in/on/near someone's tracks be safer than riding, say, 10 ft left or right?

Thanks for any info.

[skifishbum]

These tracks you speak of
hippy dippy wasatch wiggle repeated jumpturn bobble head direct in the fall line
Or
Hcac bmf hauling mucho ass no more than 3 per 500ft possibly encompassing the entire slope
Because I'd factor that into my personal well it's not a red flag sign of instabilty equation

[Core Shot]

These tracks you speak of
hippy dippy wasatch wiggle repeated jumpturn bobble head direct in the fall line
Or
Hcac bmf hauling mucho ass no more than 3 per 500ft possibly encompassing the entire slope
Because I'd factor that into my personal well it's not a red flag sign of instabilty equation

Not quite sure what that means


But fuck yeah, if there’s tracks, you gotta send it!!!!!!!!!!!!!!!!!!!!!!

I might need more exclamations!!!!!!

[stealurface831]

Not quite sure what that means

sometimes i try really hard to understand sfb and never quite feel like i do.

[tgapp]

Too many variables here.

1. How many tracks
2. How old are the tracks
3. What the shape of the slope is (are there rollovers or other weird complexities where there aren't tracks)
4. What the shape of the tracks are (like sfb was saying - were there people farming the shit out of the slope or just a few folks who bombed it?)

If you don't know, you shouldn't go in my opinion. Tracks don't indicate a lack of instabilities, only that the previous skiers didn't trigger any. It could have warmed up, wind loaded, or otherwise changed between now and when they made them - or they could have gotten lucky, known something you didn't know, or just skied in the right place.

If, given the avalanche danger and your own observations, you decide that some terrain is off limits for whatever reasons (skiing solo, likelihood of triggering a slide, a particular avalanche problem, whatever), I would recommend exercising discipline and learning to walk away. Discretion is the better part of valor.

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[snowaddict91]

Too many variables here.

1. How many tracks
2. How old are the tracks
3. What the shape of the slope is (are there rollovers or other weird complexities where there aren't tracks)
4. What the shape of the tracks are (like sfb was saying - were there people farming the shit out of the slope or just a few folks who bombed it?)

If you don't know, you shouldn't go in my opinion. Tracks don't indicate a lack of instabilities, only that the previous skiers didn't trigger any. It could have warmed up, wind loaded, or otherwise changed between now and when they made them - or they could have gotten lucky, known something you didn't know, or just skied in the right place.

If, given the avalanche danger and your own observations, you decide that some terrain is off limits for whatever reasons (skiing solo, likelihood of triggering a slide, a particular avalanche problem, whatever), I would recommend exercising discipline and learning to walk away. Discretion is the better part of valor.

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Yup. And after you answer all those questions go ahead and throw the logic out the window. Buried weak layer don't give a fuck about tracks when you hit the right spot.

[tgapp]

Yup. And after you answer all those questions go ahead and throw the logic out the window. Buried weak layer don't give a fuck about tracks when you hit the right spot.

Yeah I was just addressing OPs question about near surface instabilities. With a pwl it's a whole different ball game. No mercy, no prediction, no logic. Just don't go there.

To OP: You do you pikachu but if I'm skiing solo on a day with considerable hazard (the winds have been nuking the wasatch pretty fucking hard lately), I'm not gonna ski avalanche terrain. Period. I don't give a fuck if some dude in a wookie suit just sent a backflip on the slope, no means no.

Everyone figures out what level of risk they're comfortable with. Maybe as you progress as a skier you'll get better and better at managing near surface instabilities, and there might be a time when you feel confident managing them solo in avalanche terrain, but if you don't know how to safely and effectively do that (or you aren't 110% confident in your abilities), you might wanna avoid that kinda shit.

At the end of the day, if you're skiing solo it doesn't matter if it's a 4" slide or a 40" slide if you lose an airway and die. They'll both kill you just the same if no one is there to dig you out. And this attitude of "well the pwl is gone so it's open season" - is a dangerous one. Am I getting on steeper and higher consequence terrain? Abso-fucking-lutely. Are there other avalanche problems that can kill you? No doubt.

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[glademaster]

I don't give a fuck if some dude in a wookie suit just sent a backflip on the slope, no means no.

As Chewy always said: "Live to ski another day."

[CirqueScaler]

Too many variables here.

1. How many tracks
2. How old are the tracks
3. What the shape of the slope is (are there rollovers or other weird complexities where there aren't tracks)
4. What the shape of the tracks are (like sfb was saying - were there people farming the shit out of the slope or just a few folks who bombed it?)

If you don't know, you shouldn't go in my opinion. Tracks don't indicate a lack of instabilities, only that the previous skiers didn't trigger any. It could have warmed up, wind loaded, or otherwise changed between now and when they made them - or they could have gotten lucky, known something you didn't know, or just skied in the right place.

If, given the avalanche danger and your own observations, you decide that some terrain is off limits for whatever reasons (skiing solo, likelihood of triggering a slide, a particular avalanche problem, whatever), I would recommend exercising discipline and learning to walk away. Discretion is the better part of valor.

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Thanks for this info. And yes, I'm just asking about the problems I named. And I'm only asking for knowledge; I'm not doubting my decision to not ski the slope today.

Edit: and really, all I'm asking is: it's been said many times this year - and in general - that tracks on the slope don't indicate stability for a PWL/deep slab-type problem (like snowaddict91 said). And I'm asking if that rule applies to the other avalanche problems that I named. Because I don't know.

[teledad]

I wouldn't put any weight (one way or another) on a few tracks regardless of the problems of the day. Too much possibility of variation, both spatially (previous skiers may have missed trigger points on the slope), temporally (conditions may have changed since they skied), and just plain random chance. Previous avalanches are obviously a red light but the lack of them isn't a green light.

[frorider]

OP asked

Would riding in/on/near someone's tracks be safer than riding, say, 10 ft left or right?

‘All else being equal — Probably Yes’ is what the science would say. But it’s rare in an actual slope for all other factors to be ‘equal’. So that Yes doesn’t help you much.

As you’ve seen, there’s a hallowed tradition in which we all pretend you asked ‘would skiing in those existing tracks guarantee safety?’ and then that question, which you didn’t ask, gets answered with the obvious No.

[mtnjam]

I was touring alone today and came across a 38*ish slope w/ 15 or so tracks on it. In Utah today, our avalanche problems were new snow problems and wind slabs/loading.

I had committed to staying out of avalanche terrain while alone, but it made me wonder: do tracks on a slope indicate stability for certain avalanche problems such as loose dry, storm slabs, or wind slabs? Would riding in/on/near someone's tracks be safer than riding, say, 10 ft left or right?

Thanks for any info.

Take an avalanche course and a simple answer to your question is NO! Do you know about F.A.C.E.T.S. or A.L.P.T.R.U.T.H.S.?

[apocequip307]

Unpopular opinion it seems, but I think tracks on a slope (with evidence that they are fresh relative to the speed of changing conditions) are a data point in decision making. It shouldn’t be the sole factor in green lighting a slope, but with only surface instability, it’s hard to argue that you are equally likely to trigger a slide on a previously skied slope as a virgin one. This certainly doesn’t mean open season, and if other days points also align with the decision to ski, it’s still important to choose micro terrain carefully (ie avoiding start zones regardless of tracks, same as you would without)

I also believe that from a surface avalanche perspective, the more confined the slope (bowl > face > couloir), the more previous tracks (again this is all relative to how quickly conditions are changing) become stronger evidence of stability.

[jono]

At the most literal this seems pretty weird: are you planning to ski right in (or even mostly in) someone else's tracks? Because, sure, that's a little safer (emphasis on the "r"). All else being equal, I think I'd prefer a slightly safer slope with no tracks. For safererness and because why else am I hiking out there in the first place?

[nortonwhis]

I think its very snowpack dependent. In the blackcomb backcountry there a couple of gnarly lines to open up, but generally once people have skied it im happy to jump in. Bearing in mind we rarely have anything but storm snow to manage, and lots of skier compaction from these lines being skied to death during and after every storm.

So for me, in my environment, yes tracks give me confidence to ski something, solo or in a group. Maybe I wouldn't open some of these lines solo, but would drop 2nd or 3rd solo without batting too much of an eyelid. Having said that we have very different snowpack to anyone outside of the coast mountains (one of the reasons its near impossible to leave here)

[teledad]

Everyone has the freedom to make their own risk assessments, but the Tunnel Creek slide at Stevens Pass was triggered by the 7th skier. Storm slab in coastal snow, stepping down to an earlier crust layer. I'm sure there are plenty of other examples.

http://media.nwac.us.s3.amazonaws.co..._2-19-2012.pdf

[Hacksaw]

To paraphrase Bruce Tremper, “Never believe that previous ski tracks are a sign of good intelligence.

[SamuelRichards]

I wouldn't put any weight (one way or another) on a few tracks regardless of the problems of the day.

[summit]

tldr; Tracks that trigger are reliable indicators of INstability that are generalizable to other slopes. Tracks without slides are not reliable indicators of stability, even on that given slope, for any avalanche problem.

Short discussion: Tracks are a weak indicator for certain problems meaning that it offers insufficient data to shift assessment and constrain uncertainty to the point where you could override you previous plan and assessment. IF you thought that slope was suspect, tracks don't offer a reason to change your mind. We seek signs of INstability. Tracks don't really confirm stability. In other problem types such as wet slab or problems encompassing hard slab such as persistent slab, tracks on a given slope are essentially meaningless in assessment of that slope.

Solo Mindset: Solo means you are going for large margins of safety and good heuristic rules for slope selection, not trying to cut razor thin margins by trying to include nebulous assessments of a slope like the presence of tracks!

Further discussion: Problems that encompass avalanche problems likely to trigger at the skis (loose and softer soft slabs) are marginally indicated by tracks vs activity, but what is not captured is how the snow was interacted with by the rider and all the components of spatial variability! That is why it is so weak. If the tracks were done by a skier gordon lightfooting turns, what does that tell you? Or a straighline? This is what skifishbum was talking about. If you watch someone pound a steep rollover point and don't see loose avalanching, then perhaps they indicate some better cohesion and bonding in the surface layer, but perhaps that is misperception of the local slope or spatial variability.

jono is also correct in that any potential indication of stability of the track is more accurate if you are literally in that track, but nobody skis that way in avalanche terrain unless you are just navigating through a hazard. We do ascend that way. What I mean by this is that you are more likely to trigger while breaking trail than while in a broken up track. The two caveats are 1. that you can still trigger from a broken track and a broken track in a bad place is not safer than breaking a new track in a safe way (ie don't be lazy). 2. You are far less likely to get red flag indicators of instability (cracking, whoomfing, etc) while in an established track (ie break a little new now and then in safe places).

The logical extension of that tracks vs stability question is the type of track more likely to trigger. Ski cuts as an assessment tool on (safe) test slopes are arguably a better assessment tool. Using this tool on a real slope is more fraught and another thread (spoiler: highly discouraged in the CO winter backcountry or wherever hard slabs are found).

The number one take away of ski cuts for assessment is that a result indicates INstability, but the false-stable rate of non-results is HIGH so they are not highly reliable indicators of stability. Some rando tracks that you didn't even see get skied in are even more likely to give you FALSE-STABLE which is why we don't trust them.

Hacksaw unsurprisingly gave the best reply quoting Tremper above.

[rod9301]

This thread needs to take into account the type of snowpack, continental, maritime etc

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[summit]

This thread needs to take into account the type of snowpack, continental, maritime etc

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I disagree.

Climates are predictive of the presence or absence of various problems at various times, but those generalizations to not specify the meaning of tracks on a specific slope on a specific day. The best you could say is that tracks without results are often a somewhat less meaningless indicator in maritime vs continental, at least sometimes. But it's ultimately dependent on the problems present, regardless of the climate, in the setting of that slope. Thus for continental, tracks without avalanches are meaningless most of the year on most slopes because of the persistent weak layers under hard slabs that are so prevalent. That's about as good as you can get. But you cannot say "tracks are meaningful in the maritime" because that isn't a reliable statement for the climate even part of the time vs the particular tracks on a particular slope on a particular day. This small piece of the puzzle offers nebulous value that is super sensitive to a particular slope on a particular day given the particular tracks and that is why they offer minimal value as an obs.

[nortonwhis]

I disagree.

Climates are predictive of the presence or absence of various problems at various times, but those generalizations to not specify the meaning of tracks on a specific slope on a specific day. The best you could say is that tracks without results are often a somewhat less meaningless indicator in maritime vs continental, at least sometimes. But it's ultimately dependent on the problems present, regardless of the climate, in the setting of that slope. Thus for continental, tracks without avalanches are meaningless most of the year on most slopes because of the persistent weak layers under hard slabs that are so prevalent. That's about as good as you can get. But you cannot say "tracks are meaningful in the maritime" because that isn't a reliable statement for the climate even part of the time vs the particular tracks on a particular slope on a particular day. This small piece of the puzzle offers nebulous value that is super sensitive to a particular slope on a particular day given the particular tracks and that is why they offer minimal value as an obs.

Yes but OP specifically called out

I had committed to staying out of avalanche terrain while alone, but it made me wonder: do tracks on a slope indicate stability for certain avalanche problems such as loose dry, storm slabs, or wind slabs? Would riding in/on/near someone's tracks be safer than riding, say, 10 ft left or right?

So this totally changes things like PWL's in my mind.
I wouldn't ski something that had tracks on it if we were in PWL season, but in a maritme snowpack, without PWL, and the only concern is recent storm so (which is precisely what the question is asking), then it would give me more confidence to ski a slope. How much confidence depends on many things, but for sure it there are no other signs of instability and someone has skied the line an hour before i get there in Coastal BC, theres a high chance im going to as well.

I understand the point of view, and continental snow packs scare the fuck out of me, but as Rod mentioned, things are very different on the coast.

[fomofo]

[toast2266]

I'd say prior tracks for new snow / storm slab / wind slab problems are a pretty good indicator. If 15 people have already laid tracks through the terrain I'm skiing and nothing budged, I'm definitely going to feel a bit better about skiing that slope.

Sure, it's far from a perfect indicator. And sure, it depends on the nature of those tracks, when they were made, what the snow has done since those tracks were made, etc. And sure, I'm still going to use every other indicator available to me to assess the risk on that slope. And sure, if I'm skiing alone, I'm going to be extra conservative and would most likely still stay off of that slope purely because it's avy terrain with fresh snow.

But at the end of the day, if 15 people have essentially made ski cuts for me, then that's great.