Avalanch expertise wanted...

[1080Rider]

What exactly are you looking for when digging a pit. Are crusty layers okay as long as there's a good bond, does it depend on the thickness of the layer? Just trying to get a little feedback. I've read a little on the topic not nearly enough. Just wondering. I would think a thin layer of crust w/ soft snow underneath and on top would be dangerous, am I right?

[Ireallyliketoski2]

Originally posted by 1080Rider
What exactly are you looking for when digging a pit. Are crusty layers okay as long as there's a good bond, does it depend on the thickness of the layer? Just trying to get a little feedback. I've read a little on the topic not nearly enough. Just wondering. I would think a thin layer of crust w/ soft snow underneath and on top would be dangerous, am I right?

What exactly are you looking for when digging a pit?
Sometimes weak layers, sometimes my keys.

Are crusty layers okay as long as there's a good bond, does it depend on the thickness of the layer?
that's just gross

I would think a thin layer of crust w/ soft snow underneath and on top would be dangerous, am I right?
Various compression tests could help to determine the weak layers in this scenario. Generally if you have a soft slab on top of a crusty layer you will see this shear easily, if the soft slab release then the energy from that could propogate a release right to the ground.

Get the book Snow Sense, great reference.

[truth]

Only ski yellow snow.

[INDY GS]

gold...you're looking for gold when you dig a pit.


no really the layers of snow, various types of snow and checking stability. There are some really useful sites that i have seen on the topic, I am a little busy right now to link all of them up here, but doa quick google, you will find some answers there. however there are no substitutes for taking a class and learning by experience. Book smarts don't translate well during an emergency.

[homerjay]

strong layer on top of weak layer = bad news. e.g. Colorado.

my level 1 course de-emphasized pits...the snow could be totally different 20 feet away.

pits are only good if the data is repeatable. The course emphasized data collection and checking the report and knowing what to expect before you leave the trailhead.

Also make sure your pit is on the same aspect and near the same elevation as what you're planning to ski.

I will recommend "Staying Alive in Avalanche Terrain" by Tremper.

[1080Rider]

Thanks guys. I need to take a class, just need to set aside the time and get it done. I'll check the books in the mean time.

[trainnvain]

Info for courses in Panhandle

A good video pick up is Winning the avalanche game .

And I second the recommendation on the book Snow Sense

[Beaver]

There are no bad layers or good layers that are always bad or good. (make any sense?) Somtimes a layer will bond well to the surrounding snow and other times a seemingly similar layer will not. There are a lot of variable like wind, temp, sun, dry air...... that will affect how layers bond. Take a good course, read lots, dig lots of pits, go out in different areas and get a feel for the snow, pay attention to the weather in the areas you will be traveling & travel smart. You still won't know for sure what you've got underfoot but you will have a lot better idea and increase your chances of having a nice day.

[iskibc]

Originally posted by 1080Rider
Are crusty layers okay as long as there's a good bond, does it depend on the thickness of the layer?

I had an old roommate in college that only changed his underwear once or twice a week. I'm pretty sure he had some crusty layers going on down there. Probably had some good bonding going on too.

[Pinner]

Just dig a pit. It doesn't matter if you don't know what you're looking at as long as you get pictures of you in it looking extremo.

[Platinum Pete]

Originally posted by homerjay
strong layer on top of weak layer = bad news. e.g. Colorado.

my level 1 course de-emphasized pits...the snow could be totally different 20 feet away.

pits are only good if the data is repeatable. The course emphasized data collection and checking the report and knowing what to expect before you leave the trailhead.

Somebody once told me that digging pits should only varify what you can surmise from looking around, knowing recent weather, knowing the terrain patterns, etc. Pits should only tell you if you know what is going on in the snowpack or not, they should not be a primary info source.

I'd love to hear some feedback on that, because I'm not sure it is complete or perhaps more conservative than necessary.

[cololi]

Basically what everyone else has said. I think little things like pole probes (sticking your pole in to feel the different layers) and using small test slopes tell a better story. Pits only tell you whats going on at the location of the pit. However, if you dig them all winter long at different elevations and aspects, you will start to see some layers that repeat themselves, regardless of location. (ex: The brown stripe that appeared in the snowpack in the wasatch last winter, and to a smaller extent this year) and this can give you a very broad idea of what you are dealing with.

[DougW]

Originally posted by Platinum Pete
Somebody once told me that digging pits should only varify what you can surmise from looking around, knowing recent weather, knowing the terrain patterns, etc. Pits should only tell you if you know what is going on in the snowpack or not, they should not be a primary info source.

I'd love to hear some feedback on that, because I'm not sure it is complete or perhaps more conservative than necessary.

Thats what I heard on my course. Courses have been de-emphasising pits compared to the past. But they still are a learning tool. My instructor made this point. You have already decided to ski, you are there ie you have already been in danger on the skin up. You dig a pit on slope near to where you want to ski. You still have to ski down from there. Better to have been continually gaining info on the way up.

The closer you make the pit ( angle, elev. ) to the area you want to ski the more danger you are in when you dig your pit. A bit of a catch 22.

He had a two minute test on the way up. Find a huge boulder with 2 meters of snow on it . Climb up and do a albeit uncontrolled Rutschblock test by trying to get it to release. How did it fail - slab how thick, how much force required.

[iceman]

Originally posted by cololi
(ex: The brown stripe that appeared in the snowpack in the wasatch last winter, and to a smaller extent this year)

Sorry about that. That Mexican food gets me every time.

[AK G-Dog]

I will third the book "Snow Sense". I have attended several lectures/seminars/classes and theirs have been the best. The book is well written and easy to understand.

Of course this recommendation comes with the standard, "Attend a class" recommendation.

Pits are a good "tool" but there really is a lot more to it then just that. The book will put it all in perspective.

[Mountainman]

My book reccomendation is The Avalanche Handbook. While probably not the best suited for specifically digging pits, it gives a great all around coverage of avalanche predicting and safety. It is also the course book MSU uses for one of their Snow Science classes.