How to identify wind-scoured slopes?

[SamWerner]

I did Mt Sherman via the South Slopes route yesterday, and in the research phase of looking at routes, I was really worried about the White Ridge that was looming to the N-NE of the route (a south-southwest facing slope). Huge chunks of it are 35-45 degrees, so I was really worried about it being avalanche prone. When we got there, it ended up being completely wind scoured with barely any snow on it at all.

My question is: Is there a way to know (or are there online resources) that can help you tell when a slope or summit will be wind scoured without seeing pictures of it? Conditions reports are few and far between in these months so it's hard to rely on pictures and descriptions. I'm assuming there's a way to look at average wind direction, slope facing direction, and other factors, but I haven't found anything online. I have not yet taken AIARE 1 (planning to in the near future) so I'm doing my best to stay away from potentially dangerous slopes by planning routes carefully, but I'm not sure what specifics to look for besides slope angle. Any help or resources would be greatly appreciated!

[SkaredShtles]

Nope.

There are generalities, but you cannot determine such a thing for sure without laying eyes on the slope.

[Eli Boardman]

In my experience, pictures from trip reports from previous years are the best resource. It's far from a guarantee, but certain slopes are almost always wind scoured, and reading trip reports will help you identify which ones are more/less likely to be snow free, especially on a well-documented mountain like Sherman.

Of course, as they say, past performance doesn't guarantee future results, but you can always turn around if the slope you thought was going to be scoured (based on previous TRs) turns out to be snowy.

[Buckie06]

Sam,
Kudos to you for recognizing such danger, and even more kudos for reaching out for help. Many people would not do this, you are a great person.

Caltopo added a new feature these past few months of weekly aerial satellite photos. Before your climb you could look at the week's aerial photo to see if there's any snow on the slope, then compare that with the week's weather report if there were any big snow dumps since the satellite photo was taken. https://caltopo.blogspot.com/2019/06/se ... kTu75Qg6kM

You can also use the SNOTEL stations located throughout the CO mountains to get a reading of the snow depth. They are usually not above ~11,000 and close to dirt roads for maintenance though. https://www.wcc.nrcs.usda.gov/snow/snow_map.html

[SamWerner]

In my experience, pictures from trip reports from previous years are the best resource. It's far from a guarantee, but certain slopes are almost always wind scoured, and reading trip reports will help you identify which ones are more/less likely to be snow free, especially on a well-documented mountain like Sherman.

Of course, as they say, past performance doesn't guarantee future results, but you can always turn around if the slope you thought was going to be scoured (based on previous TRs) turns out to be snowy.

That's definitely a good idea, I'll check those out next time for a good starting point!

Sam,
Kudos to you for recognizing such danger, and even more kudos for reaching out for help. Many people would not do this, you are a great person.

Caltopo added a new feature these past few months of weekly aerial satellite photos. Before your climb you could look at the week's aerial photo to see if there's any snow on the slope, then compare that with the week's weather report if there were any big snow dumps since the satellite photo was taken. https://caltopo.blogspot.com/2019/06/se ... kTu75Qg6kM

You can also use the SNOTEL stations located throughout the CO mountains to get a reading of the snow depth. They are usually not above ~11,000 and close to dirt roads for maintenance though. https://www.wcc.nrcs.usda.gov/snow/snow_map.html

That's exactly what I was looking for, thank you! I'll have to play around with the settings on that Sentinel map so it's easier to follow, but that is a fantastic resource. I'll check out the SNOTEL stations as well, those seem like they may be more reliable than the ski resorts telling me to expect 15 feet of snow.

Thank you also for the kind words! I know I'm just getting started in mountaineering, and I rather enjoy not dying in avalanches, so I figured this was a great place to start.

[daway8]

If you're looking for general avalanche evaluation you might benefit from the analysis I've done in a couple of my trip reports which point out some things to look for - certainly not a substitute for proper training but you might glean a few useful things in the meantime since there are some warning signs you can spot ahead of time:

https://www.14ers.com/php14ers/triprepo ... m=tripmine
https://www.14ers.com/php14ers/triprepo ... m=tripmine

Also, if you've not seen it yet, another good resource is this site with descriptions of all the 14ers in winter https://www.summitpost.org/colorado-14e ... ter/337648. Don't trust this 100% either but it's a good starting point combined with the analysis tips above plus learning, research and on-site evaluation.

[TomPierce]

Sam,

Good job on Sherman! I was the fellow across the valley from you on Mt. Sheridan yesterday, I watched your progress off & on all day.

The Caltopo link above for weekly photos is a new one to me, I'll have to check it out. I've had limited luck with Snotel, just too much variability once you get away from the exact spot they measure. But you're on the right track, if a line is wind-scoured you'll be fine if you stay on the rocks; you have to have snow to have an avalanche. Fwiw, that area is notoriously wind-scoured, the slopes that will slide are pretty well known and relatively easy to avoid.

Another idea is to bone up on avalanche route-finding. There are several online tools that will help. Years ago I found a fun online exercise tool developed by the Canadians. It's not a substitute for a good field course, but it gets you thinking. Take a look, it might be useful for you:

https://www.avalanche.ca/tutorial/reduc ... -exercises

Be safe out there.

-Tom

[SamWerner]

Sam,

Good job on Sherman! I was the fellow across the valley from you on Mt. Sheridan yesterday, I watched your progress off & on all day.

The Caltopo link above for weekly photos is a new one to me, I'll have to check it out. I've had limited luck with Snotel, just too much variability once you get away from the exact spot they measure. But you're on the right track, if a line is wind-scoured you'll be fine if you stay on the rocks; you have to have snow to have an avalanche. Fwiw, that area is notoriously wind-scoured, the slopes that will slide are pretty well known and relatively easy to avoid.

Another idea is to bone up on avalanche route-finding. There are several online tools that will help. Years ago I found a fun online exercise tool developed by the Canadians. It's not a substitute for a good field course, but it gets you thinking. Take a look, it might be useful for you:

https://www.avalanche.ca/tutorial/reduc ... -exercises

Be safe out there.

-Tom

Thanks Tom! You must have been either the car there way before us or the one who pulled up as we started up the road. I tried out that Canadian route finding link, that was really cool! I think most of the scenarios involve being closer to sketchy terrain than I'd be comfortable with in real life (at least without all the training and gear), but it definitely helped illustrate what the hazards look like on an actual mountain rather than a diagram.