UKC

I was talking with my mate the other day about our trip this summer and we both agreed the scariest moment was after coming down Mont Blanc du Tacul and crossing the Valley Blanch in the late afternoon to get back to Aguille du Midi.

Normally the most uneventful and mondaine part of the day right?

It was in August I think, and the middle of the heatwave.

There was a fair few people in front and we blindly followed the path that everyone was using.

We got to the middle of the Valley Blanche, at its lowest point and suddenly found our feet were sinking straight through the snow to just beyond knee level.

This was the lowest point of Valley Blanch Col du midi right at the head of Glacier de Bossons (if I’ve got my glacier names right). I.e. perfect place for crevasses to open up.

Those behind and in front didn’t seem to mind that their legs were sinking every other step, but it seemed to risky for us, so we opted to turn 90 degrees and walk east to where we felt crevasses would be less likely and then found a parallel path that nobody was using and followed that instead.

When chatting to others, they didn’t seem too concerned about the valley being slush and said it’s to be expected when hot, which, ye, I get.

Was there a real elevated risk here, or were we just being paranoid of the what ifs?

Common sense tells me that if nobody else thinks it’s a problem then it probably isn’t but the summer of 2022 was pretty exceptional in terms of heat so did we all just get lucky?

Interested to know what others think?

What makes you say that ?

Being close to the head of a glacier, the underlying ground goes from being quite flat to suddenly quite steep so I can imagine a lot of tension tracks appearing.

If you look at this photo,

https://static.wixstatic.com/media/450e22_5a60323b86ef4530bac699846b473c2c~...

just above where the tents are, on the right, you can see the ground starts falling away and the colour changes from white to grey.

I would have thought this is a prime place the cravasses to be as the valley ice is being stretched.

It was this point where we were sinking in.

So we walked east, left on the picture which felt a lot safer.

Yes and no, think of a crevasse as a loaf of sliced bread, it will fan and open up according to terrain beneath, or the outsides as it turns down valleys. 

There are crevasses if you head off toward the pyramid, below the decent ridge there are also shrunds where the glacier breaks away from the ridge. 

No where is zero risk though, flat areas such as there are lower risk than pretty much anywhere you'll have been that day. 

Do you mean the wind hollow around the rock buttress, or am I misunderstanding you? Did you walk more or less where the red line is (is it your photo?)

As Exiled says, flat areas are *generally* the safest parts of the glacier. Crevasses tend to form over convexities or on the outside of bends.

It's not my photo, just one that I found, and yes we did walk roughly along the red line.

So this was walking back, so as you look left (right on the image) there are loads of cravasses as the ground falls away down to chamonix.

So it was on the red line, level with where the text for "Col du Midi basecamp" is.

Well I'd say that the risk along that line was absolutely minimum. You can't cut risk out of the equation altogether, you can only reduce it. Which is what you did. 

To me it just felt like the main path was far too close to the edge of the flat area if you will.

Had the ground have been solid, it would have felt fine, but sinking through definitely gave me a very uneasy feeling and i wanted to be more in the middle of the valley, not the near the edge where the ground must be convex not too far away where it transitions from the col du midi to the bosson glacier.

You are to be congratulated on thinking for yourself.

Sounds like you'd have really struggled to haul someone out if they'd gone through, given the soft snow. Personally I'd probably have been pretty nervous and changed tack the same as you.

I'd have thought you were more at risk descending through the seracs on the Tacul face though, given the temperature and time of day. I guess it just depends on how much you like rolling the dice, I was in Chamonix in august, it was bloomin' hot and we avoided glaciers entirely as my appetite for that kind of gamble is pretty low.

The path is a shared trail of averages, no one wants to break a new trail and have 3 independent lines to tacul, the hut and start of cosmiques.

If you're sinking it's just soft, if it was a collapsed bridge you'd know! I'm not saying it's 100% safe, it's not, i always rope up with someone around there, even if many others don't. There is an element of the unknown, as we can't see through the snow, so I'm sure views will differ. 

Edit. If it was that warm and soft i would want to be way out from below the arete, even if that meant breaking trail. Big chunks have fallen off regularly in recent summers.

Good thought about processes and thinking about safety. However cols are usually crevasse free areas because the ice at any col is usually compressed by the force of any ice from the slopes above it. So for instance any of the large crevasses forming on the Tacul face, as they move down the slope onto the Col du Midi will be forced closed. Once you are off the flat col area, then the movement of the glacier will allow the crevasses to open. Compression rheology.

Aug 2017, a hot-ish day, coming back from doing a route on the Dent du Geant, was maybe 300m from the Helbronner lift, I went through a snow bridge into a bottomless crevasse. If I hadn't been on a rope, I wouldn't be typing this.

Similar circumstances to you, we were on the "established path" although there were parallel options. We had discussed the snow conditions (it was a hot summer), were the 2nd team on the route and were moving very well, and had cruised guidebook time but perhaps because it had gone so well and to plan, we maybe stopped thinking as critically and were just happily blasting home on the "path". There were at least 10 other teams on the route, so group think can give you an artificial sense of comfort, and make it even easier to fall into heuristic traps.

I don't think there's any harm in stopping and reassessing your situation, as what may have been safe 1min/1hr/1day before, could now be different  

Funnily enough, the group in front of us had something similar happen coming down Tacul where there was a bridge crossing a crevasse, maybe half way up the slope.

We saw this lass fall through. Fortunately she was in the middle of a group of three so didn't fall very far and managed to scramble out whilst the guy in front leant back on the rope.

I thought the guy at the back did really well to hold it as it was quite steep down to the crevasse.

I remember on the way up thinking the bridge was dodge as hell. It was nothing more than a lump of ice that must have rolled down from somewhere on got lodged in the crevasse.

I'm not entirely surprised you went through there, it's a slightly curved area with the glacier splitting with some heading into France and the rest Italy. 

This logic is the reason why we moved more into the middle of the col.

I think the path gets as close as maybe 30m from the edge of the col where it becomes very steep at the head of Bosson Glacier. The bit I'm not clear on is how likely they to open up 30m away form the edge.

You're probably right and it's very unlikely but that uncertainty whilst falling through gives me the hibbie jibbies.

the mistake you made was being up there mid afternoon in august in the first place! beyond that you thought for yourself rather than blindly following others, and that is always a good thing.

Chamonix is really not the place to be comming for alpinism in August any more at the best of times, and this year was exceptionally bad. come in May/June, or go somewhere else if you cant. The concept of 'summer alpinism' doesnt really apply any more and things are only going to get worse...

I'm quite limited to summer at the moment as it's the school holidays. The tricky part is you never know if it's going to be July that's roasting, or August, or maybe they're both freezing.

Just part of the gamble I guess.

I went to the The Mer de Glace and found it shocking to see the glacier levels that were signed posted as near as 2010, or 2005 and the difference in level compared to now. Quite sad really.

I don't know why your post got disliked when it is pretty accurate......

If you're limited to school holidays you could always try a week around May half term? I think you are probably more likely to have acceptable snow conditions then, although if it is a snowy winter and spring then skis/snowshoes can be useful

I'm going to sound like I'm full of excuses, but with a week I generally struggle with acclimatising.

To enjoy it I need two weeks there.

That leaves March or Summer.

March might be perfect in 10 years.

Oh, and while you're there, was this with the guy who didn't want to be roped up with you ? Did he change his mind ?

I'd suggest the risk on a path 10s or 100s have followed without incident is lower than going over virgin snow.

yes and he did.

Back in the eighties we descended a glacier described in the guidebook as safe without a rope as according to the text  there where no crevasses even though it wasn't a dry glacier. I went through with both legs but managed to stop going in. It was deep with a big sounding stream below. We roped up quick after that. Looking back it was very hot and obviously global warming in action. It taught me always to stay roped on snow covered glaciers no matter how safe it seemed, and no matter what the guide said.