Inbounds avalanche

[kimbo]

Did anyone else see the small inbounds slide at Perisher on Saturday morning? In the bowl between the Terminal Quad and Sidesaddle.

Looks like it released on Friday evening/early Sat morning. Crown face of about 20-30cm, full width of the bowl. I suggest it was HS/I/R4D1/UO. (Hard slab, failed at new/old snow interface, large size relative to its path but low destructive force, unknown trigger). It had an ENE aspect which would suugest that it was top loaded as the wind over the snowfall period had been consistently NE.

Unfortunately I didn't get a chance to have a close look or do a profile.

[SA]

Bear has some pics of it in Pod's weekend report thread.

[ 06. July 2009, 11:52 AM: Message edited by: SA ]

[kimbo]

SA, those pics are a different slide on Interceptor. Interesting to note debris looks like slab thickness about the same.

[SA]

Ah right, didn't know there was more than on at PB on the w/end.

[Podlettte]

Hey Kimbo - I don't know the avalanche/slide terminology, but the one on interceptor was deeper than 20-30cms, more like 40-50cm and slide probably 20m?

it was interesting to note that just below it and towards where Bear and I were standing there was another crack running straight across the slope and it followed the line of one of the rocks just below the slide, there was one spot I noticed, before some snow compressed beneath my downhill foot and I fell over ;) , that I could see through to a blue layer, like I was looking into a crack in a glacier.

the crack ran across the whole section of slope left and right under the slide area, so potentially more to come! I pointed it out to a friend who's a patroller

[Podlettte]

and the area you're talking about is called the Gulch if I've got the right place... Is it the steep part that's between the run down to the terminal chair and the run down to both summit and terminal about 50m 'north' of the terminal run?

[Podlettte]

Originally posted by Podlettte:
Hey Kimbo - I don't know the avalanche/slide terminology, but the one on interceptor was deeper than 20-30cms, more like 40-50cm and slide probably 20m?

it was interesting to note that just below it and towards where Bear and I were standing there was another crack running straight across the slope and it followed the line of one of the rocks just below the slide, there was one spot I noticed, before some snow compressed beneath my downhill foot and I fell over ;) , that I could see through to a blue layer, like I was looking into a crack in a glacier.

the crack ran across the whole section of slope left and right under the slide area, so potentially more to come! I pointed it out to a friend who's a patroller http://i186.photobucket.com/albums/x242/podlettte_/P1080937.jpg

You can see the line where it's broken and the bare area that's been partially filled by windblown snow.


http://i186.photobucket.com/albums/x242/podlettte_/P1080932.jpg

[John Deere]

70cm of dry snow plus wind loading on a boiler plate layer is not going to be stable in any country for the first few days.

[Podlettte]

I wasn't expecting it to be, but then I've never seen a slide inbounds at Perisher/Blue cow since I started skiing and haven't read any threads about them, I guess that's why it's interesting!

Last year proved/brought it home that Aus isn't immune to slides, although those circumstances were a little different ie human triggered.

[John Deere]

There was a small slide inbounds at PB last year, skier triggered. It was in one of their promo vids, would have buried anyone due to it being on a fairly low angled sope, but still, showed the potential for surrounding areas at that time.

Certainly the one in your pics is far more significant, although it looks like it went slowly and didn't travel very far......got any wider angle shots of it...anybody??? Be interesting to see what it looked like in the context of the hill it was on the side of.

[Blowey]

Interesting.

There was a 30-50m slide at the top of the bluff on Friday morning and the slab was at least 1m thick. I didn't see it go, only saw the debris. Later in the day a mate triggered a small slide at the top of Michaels mistake. Luckily it was only a small wind loaded cornice at the very top of the run. It only went about 10m but was about 1m thick also.

[Blowey]

This weekends rain should stabilise the snow pack a bit.

[Pini Pow Pow]

I snuck out to the golf course on saturday and it was a little unstable. The snow was very wet and cracks were forming all over the place. It wasnt really steep enought to slide however...

[kimbo]

it was interesting to note that just below it and towards where Bear and I were standing there was another crack running straight across the slope and it followed the line of one of the rocks just below the slide, there was one spot I noticed, before some snow compressed beneath my downhill foot and I fell over , that I could see through to a blue layer, like I was looking into a crack in a glacier.

Podlette

Very interesting observation. You experienced two avalanche warning signs 1)cracking of the snow, which you correctly identified as a concern; and 2)the "collapse" (known as a whumph) under your foot. Did the collapse make a noise? Where you wearing your ski at the time? If the collapse was due to a weak layer trapped between the base and the slab, it should make a "whumph" sound. Was this the case? If that is the situation it would indicate that there may be a hoar layer and these tend to persist. Think I might go digging snowpits next weekend.

[Podlettte]

No, I don't JD, kept thinking I should take one from the chair, but I kept forgetting.

Bear, do you?

when you come up out of midstation it's on the right about 10-20m from the chair above the narrow bit leading to the flat run to midstation....?

I'll get a trail map and mark it

[kimbo]

and the area you're talking about is called the Gulch if I've got the right place... Is it the steep part that's between the run down to the terminal chair and the run down to both summit and terminal about 50m 'north' of the terminal run?

Podlette

That's the one! Makes for a good little natural halfpipe to finish Sidesaddle or a nice jump to finish the home run from Guthega (if you've still got enough speed)

[Podlettte]

yeah wow, I've never seen a slide inbounds, but there would be a good spot! windloaded to the hilt I imagine as the wind comes across the desert and creates a bit of a cornice in the right conditions, or simply just more snow at the top than the bottom so heavy at the top etc

[snowman]

Originally posted by kimbo:
Did anyone else see the small inbounds slide at Perisher on Saturday morning? In the bowl between the Terminal Quad and Sidesaddle.

Looks like it released on Friday evening/early Sat morning. Crown face of about 20-30cm, full width of the bowl. I suggest it was HS/I/R4D1/UO. (Hard slab, failed at new/old snow interface, large size relative to its path but low destructive force, unknown trigger). It had an ENE aspect which would suugest that it was top loaded as the wind over the snowfall period had been consistently NE.

Unfortunately I didn't get a chance to have a close look or do a profile. It was only small rode out the side.......

[skijacski]

I have seen a few at Thredbo in bounds, but driving back from Canberra yesterday, MM and I noticed that Stanleys has gone/slide. Lots of unstable slabbing.

If you were in there when it happened you would have ended up in the creek under the snow.

For those who go there often, remember this is out of bounds. Safety first.

[Blowey]

Originally posted by skijacski:
I have seen a few at Thredbo in bounds, but driving back from Canberra yesterday, MM and I noticed that Stanleys has gone/slide. Lots of unstable slabbing.

If you were in there when it happened you would have ended up in the creek under the snow.

For those who go there often, remember this is out of bounds. Safety first. Was this stanleys itself or the next gully north. I just added a page to ozbc on stanleys and included a small speel on avie potential on the gully just north of Stanleys. I've seen debris up there a few times before.

I got some photos of the area on Sunday morning. I'll have to have a closer look at them.

[Andrew & Fi]

Hi Kimbo,
Just a chance but do you live in Kingston also?