/ Avalanche reports

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kingjam - on 14 Mar 2013
All

Quick questions looking at the SAIS report for Nth Cairngorms.

Given the conditions what would cause cornice collapse im guessing the cornices are getting pretty big (heavy) rather than anything temp related .

And cross loading what is this exactly ? From the description sound likes its very localised wind slab formation ( with in a gully or slope )?

cheers
depthhoar - on 14 Mar 2013
In reply to kingjam:
> All
>
> Quick questions looking at the SAIS report for Nth Cairngorms.
>
> Given the conditions what would cause cornice collapse im guessing the cornices are getting pretty big (heavy) rather than anything temp related .
>
> And cross loading what is this exactly ? From the description sound likes its very localised wind slab formation ( with in a gully or slope )?
>
> cheers

Cornices that build (form) very quickly are often more prone to collapse, so if a lot of drifting is expected then cornice development is likely to be rapid and cornices correspondingly fragile. (It's not always as simple as that but it's not a bad rule of thumb).

Cross-loading is when windslab is deposited by winds which blow (more or less) at right angles to the fall line of a particular slope. Visualise a wind blowing along a valley....any little or large gullies/stream-beds that run down the valley sides will fill with wind-blown snow because of cross-loading. The very top of wide or multi-aspect Scottish gullies can have windslab on one side but not on the other due to the same process. The top of the 'The Vent' in Coire and Lochain in the Cairngorms is a good example of where this can happen in certain wind/snow conditions.

Hope this helps.
kingjam - on 14 Mar 2013
In reply to kingjam:

Yes thanks for the explanation
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Dave Kerr - on 14 Mar 2013

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