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Scrooge
Famous Grouse



Joined: 16 Dec 2001
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Location: wishful thinking
Scrooge
Famous Grouse
PostSat Sep 20, 2008 1:38 am 
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I was not going to do a TR on this trip, at all, but Yana's poll about risk (and my response to it) got me to thinking. Maybe there was something in that trip worth talking about, after all.

It's a dull time at Big Four, the waterfalls are mostly gone and the caves aren't yet fully developed. The dangers I discussed in "Thin Ice" are mostly gone, although the ice over some of the caves is getting too thin for confident walking. The question, now, if you're me, is whether or not to go in the caves, themselves, and how far?

The one most pertinent is Snow Cave IV, the one furthest west along the base of the cliff, the one that develops from the pair of waterfalls that come down in that far corner.

I've been fascinated by that pair of waterfalls since I first started going out there. Here's my very first picture of a waterfall coming down the cliff and disappearing into the moat between cliff and ice.

Ice Cave bergschrund falls, 2002. You really can't tell that it's my very first shot, crouched up on the edge of the ice, trying to see where the water disappears to.
Ice Cave bergschrund falls, 2002. You really can't tell that it's my very first shot, crouched up on the edge of the ice, trying to see where the water disappears to.

I didn't used to go back to Big Four every week, the way I seem to, now, so it was several years before I got another picture of those west end falls.

West waterfalls verticle pan, 2007. The camera's much better, but you still can't tell that I'm shooting from the edge of the ice down into the moat.
West waterfalls verticle pan, 2007. The camera's much better, but you still can't tell that I'm shooting from the edge of the ice down into the moat.

With a still newer camera, I rectified the shooting location ommission with this movie, earlier this year.



That pretty much puts the whole thing together,      wink.gif      and provides an introduction to this trip, in which I try to reach those falls from below, by way of the snow cave that forms each year above the runoff channel.

Approaching Snow Cave IV. Covered in avalanche debris and invisible from the rest of the snowfield, this last of the caves to open up is not very impressive.
Approaching Snow Cave IV. Covered in avalanche debris and invisible from the rest of the snowfield, this last of the caves to open up is not very impressive.
Snow Cave IV. In this direct view, you can see all the way through. It's only about 50 yards long. The waterfalls in the introductory pictures are just visible above the snow, much reduced from their earlier volume.
Snow Cave IV. In this direct view, you can see all the way through. It's only about 50 yards long. The waterfalls in the introductory pictures are just visible above the snow, much reduced from their earlier volume.

In spite of all the "mess" around the entrance, the avalanche debris and the rubble, there's no sign of any weakness in the ice; no sagging of scalloping of the ceiling and no icy breakdown on the floor. That does not mean that it's safe, but it does suggest that the risk is low. Unfortunately, that assessment must be revised rather promptly.

Snow Cave IV from the entrance. The opening at the far end is now clearly visible, although it's still not quite clear what you're seeing.
Snow Cave IV from the entrance. The opening at the far end is now clearly visible, although it's still not quite clear what you're seeing.
Oops! All right. Now it's clear. That's ice, not glistening rock.
Oops! All right. Now it's clear. That's ice, not glistening rock.

Even from the entrance, you begin to suspect that the debris at the end of the tunnel may be ice. From a little further in, there's no question; it's ice and some of it is freshly fallen. All those gleaming white surfaces are the indicators of recent breaks. ....... And at this point you know you can't go all the way out. It doesn't matter that the ice isn't continuously falling, may not even be falling as often as once a day. The risk is too great. You don't know that your presence wouldn't be the factor that would destabilize things further.

This is where I stopped, about 50 feet from the entrance. That's fresh ice, and more than just one fall, by the looks of it
This is where I stopped, about 50 feet from the entrance. That's fresh ice, and more than just one fall, by the looks of it
Here's a photographic detail that shows what's there better than I could see, just looking. There's debris from at least three separate collapses.
Here's a photographic detail that shows what's there better than I could see, just looking. There's debris from at least three separate collapses.

Yes, I continued a little further, not with the idea of "chancing it" and going out, but just enough to get a better look at the debris, to try to learn more about what's happening. You can see that this upper entrance is an area of active collapse. The photographs show three, and possibly four, distinct events. The oldest fall is in the foreground and on the left, the dark grey, smoothly glistening ice. It's been there long enough to melt and refreeze several times, producing the smooth surfaces.

At the upper left, and in a narrow strip in the middle, is what appears to be ice from an intermediate fall. I can't describe it well, but the appearance is somewhere between the old, gray ice, and the gleaming, angular breakdown beyond it that is clearly from a recent fall.

It also looks to me like there are two parts to the most recent fall, one of consolidated ice (the fragments onthe right) and one of unconsolidated snow (the irregular pile in back). I'm guessing.      rolleyes.gif

It doesn't matter. This risk is obvious. This is a point where you say, "No". The objective doesn't matter. This is not the day. ....... Maybe next time.

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Something lost behind the ranges. Lost and waiting for you....... Go and find it. Go!
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Hiker Mama
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PostSat Sep 20, 2008 11:49 am 
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I'm glad to hear you talking about the risks.  It sounds like you made  wise decision this time.  Thanks for the update, too.  I didn't manage to get there at all this year, after going multiple times each year for the past several years.  I miss it.  So I appreciate seeing your pictures!
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gone
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Joined: 08 Feb 2008
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PostSun Sep 21, 2008 9:09 am 
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That video is great and lends a perspective to the whole scene that the photos just can't - thanks for sharing it!  Be careful!  up.gif
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Scrooge
Famous Grouse



Joined: 16 Dec 2001
Posts: 6966 | TRs
Location: wishful thinking
Scrooge
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PostSun Sep 21, 2008 1:22 pm 
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Caved in, 10-23-07
Caved in, 10-23-07
Snow caved, 10-23-07
Snow caved, 10-23-07

Do the snow cave roofs ever collapse? Sure they do. The pictures above are of the remains of Snow Cave III at the end of the season, last year. Those are some big blocks of ice!

The cave that forms each year at the base of Big Four's biggest waterfall is particularly vulnerable. For some reason, the amount of snow that the avalanches deposit at that point is relatively small, compared with the rest of the cliff base, but the snow cave that forms is often the biggest one there. The result is a comparatively thin roof.

Snow Cave III entrance
Snow Cave III entrance

Comparatively. ....... But this opening didn't form by collapse; it formed by melting back into a deep, heavily compacted mass of frozen snow. The size of the arches that form gives you some idea of it's strength. Or, if you'll look at the first two photographs, notice the size of that unsupported overhang (it's 6 or 8 feet).

Snow Cave III from the entrance, waterfall visible under the right hand arch..
Snow Cave III from the entrance, waterfall visible under the right hand arch..

As with Snow Cave IV, there is no sagging or scalloping of the cave roof, and no sign of icy breakdown on the floor. The big wedge of ice in the middle does bother me. It's obviously much heavier that the adjoining sections of ceiling and I think it's likely to pull that bit of roof down, at some point. ........ Probably not right away, though. I have a picture that I took two weeks earlier that looks exactly the same.

It's an odd formation, till you realize that the wedge was once a column. Then, in early summer, when the flow of Big Four Falls was at it's maximum, a surface stream developed in the drainage channel (you can see the right hand bank quite clearly) and the base of the column was eroded/melted away. The roof held up, anyway. ......... Side note: the drainage from all the Big Four waterfalls flows underground (through the rubble) most of the time, to surface further away from the cliff.

Snow Cave III passage
Snow Cave III passage
Big Four Falls from Snow Cave III
Big Four Falls from Snow Cave III

Continuing down the cave passage and approaching the rear entrance, there is still no sign of weakness or collapse. That does not mean it's safe! I don't think I've ever spent any length of time in an ice cave when I didn't hear rocks falling from the ceiling.

Rocks falling from the ceiling?       confused.gif       Ya. The avalanche cones that the caves form in are full of debris, rocks and sticks and logs and whathaveyou. As the caves grow, melting back from the original channel, that debris is exposed, melts loose, and drops to the floor ..... THUNK ..... or onto your head.         paranoid.gif        It is, perhaps, a form of Russian roulette, but the proportion of empty chambers is very high.

Snow Cave III, base of falls. Note the absence of icy breakdown.
Snow Cave III, base of falls. Note the absence of icy breakdown.

I've included this detail from the rear entrance to the cave to emphasize the lack of any icy breakdown. Contrast this area to what was visible at the end of the tunnel in Snow Cave IV.

So, okay, maybe entering Snow Cave III was less risky, but it was still dangerous, so why do it? Why take any chance at all? ....... You do know the reason, even if you don't share the urge. Why scramble up that last rocky pinnacle or dive along a coral reef?       wink.gif         Maybe it's just to take these pictures.

Moat and waterfall detail, Big Four Snow Cave III.
Moat and waterfall detail, Big Four Snow Cave III.
Snow cave waterfall 09-04-08
Snow cave waterfall 09-04-08

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Something lost behind the ranges. Lost and waiting for you....... Go and find it. Go!
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ActionBetty
Im a dirty hippie!



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ActionBetty
Im a dirty hippie!
PostMon Sep 22, 2008 3:40 pm 
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I bet I could drive my ATV inside one of those  lol.gif

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"If you're not living good, you gotta travel wide"...Bob Marley
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Scrooge
Famous Grouse



Joined: 16 Dec 2001
Posts: 6966 | TRs
Location: wishful thinking
Scrooge
Famous Grouse
PostTue Sep 23, 2008 9:56 pm 
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ActionBetty wrote:
I bet I could drive my ATV inside one of those  lol.gif

Yep. That's what Charlie said.       agree.gif

Caved in, 10-23-07
Caved in, 10-23-07

Far as I know, he's still in there.        huh.gif

All that noise causes a lot of vibration.

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Something lost behind the ranges. Lost and waiting for you....... Go and find it. Go!
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