Avalanche Trap Dyke

[blacklab2020]

As one who was looking to climb the dyke 3 days before this happened. I know that the conditions up there were as follows (from talking with climbers who did the route and guides): The slabs were blown clean for the most part, I saw this from above and from a slide on Algonquin opposing colden. Both the guide and the climbing party said the dyke was FILLED with lots of snow up to the steep section of ice which was reduced to a 15 foot climb because there was soo much snow in below the steep section. The climbing party also mentioned they sent a fracture out across the snow right at the steep section before nearing the slab. The R & R guide suggested to me that avalanche danger would come from within the dyke rather than the slabs above.

With the rain from the weekend that I was there and more rain over the following few days it would make sense that the drainage coming down the dyke water logged the snow... Making it very wet, heavy and lubricated to move fast and similar to slush... and spread out fast at the bottom.

Edit: Although these were the conditions present the runout is huge... if anything did come down the slide it would have had to enter the dyke high up, as indicated by the vegetation remaining on the slabs in the pictures.

 

[yonkers]

I agree with Grumpy. That stand of trees below the slab would probably be gone. ?

yes definitely, i see that now . i haven't been up there in years, just trying to understand how the snow fell. Never realized the possibility of that size of a avalanche there, seeing is believing.

 

[NYBRAD]

Like TCD I’ve also either retreated above the last steep pitch or cancelled the climb more times than finishing the route. On one attempt we also caused a fracture across the dyke just before the last pitch and retreated mainly because there was a party below us. Sometimes huge bus size cornices can form on the edge of the open slabs looming over the dyke itself. If one of these fell into the dyke it could cause a slide. My theory is that this slide started as a ice avalanche caused by a water dam that caused pressure to build until it literally exploded and rushed down the Dyke.

 

[Pete_Hickey]

yes definitely, i see that now . i haven't been up there in years, just trying to understand how the snow fell. Never realized the possibility of that size of a avalanche there, seeing is believing.

If you've been up the dike, you know that:

1) snow is deposited there after being blown from the slabs.

2) It is a long, deep chute, and once the snow starts moving, it'll go.

This is not at all surprising to me.

 

[Tom Rankin]

Here is another shot from 2/28/7 - Taken from the summit of Algonquin.

http://viewsandbrews.com/temp/TD2.jpg

It doesn't quite show the bottom, and it is a little big, 305K

 

[prino]

Great shot Tom!
The slide looks pretty heavy with snow and ice .... that's 2 weeks before the Avalanche.
According to Black Lab the slides were clean 3 days before the event so I would guess the Dyke must have filled up within that time span, then with the warm temps and heavy rain just washed straight on down.

 

[iceNsnow]

Anyone interested?

I'm thinking that since the snow came down it would be a safe time to investigate. Anyone else interested?

Inge

 

[Tom Rankin]

I'm thinking that since the snow came down it would be a safe time to investigate. Anyone else interested?

Inge

This looks like it might have been a 'real' avalanche, in that trees and other debris may have been dislodged. If that's the case, the area may be very unstable, and I for one would not want to go in the near future.

 

[blacklab2020]

My theory is that this slide started as a ice avalanche caused by a water dam that caused pressure to build until it literally exploded and rushed down the Dyke.

Agreed ... There were several layers of icy crust within the snow that would certainly hold waterdam potential.

the slides were clean 3 days before the event so I would guess the Dyke must have filled up within that time span

The dyke usually takes a season to fill up to the extent that it was backed up with snow. Certainly it will avalanche from time to time, but given the unusually unconsolidated snow underneath a few crusty layers, this years conditions seemed to lend much more to instability in the snowpack and warming and rain, certainly did not help.

 

[yonkers]

If you've been up the dike, you know that:
1) snow is deposited there after being blown from the slabs.
2) It is a long, deep chute, and once the snow starts moving, it'll go.
This is not at all surprising to me.

when was the last time there was such a large deposition field that was that high and across the lake to the summer trail? i admit i find it very surprising .

 

[adirondacker]

Trap Dike- a different look

Photos from Saturday March 24.

 

[iceNsnow]

Nice shots!

Thanks for sharing your photos with the rest of us!
I'm still hoping to get there before everything ends up in the bottom of the lake.

Inge

 

[yvon]

Photos from Saturday March 24.

It look different of my pics after only one week.