How is it possible that by decreasing pressure on an ablation area (due to stress reduction) an an enhancement on ice motion is obtained.

I’m trying to figure out how is it possible that by decreasing pressure on an ablation area (due to stress reduction) an an enhancement on ice motion is obtained. It would be very useful for me if you could explain it through a simple example cause I’m not a scientist. Thanks!

Asked by Gus

Dear Gus,

Ice velocity is driven by the weight of the ice and surface slope. A glacier is a pile of ice, and as such, deforms under the force of gravity. Glaciers flow downslope because they accumulate mass (ice) in their upper portions (from precipitation and from wind-blown snow) and ablate (melt, sublimate and calve ice bergs) in their lower portions.

Glaciers always flow downslope through the processes of ice deformation and basal sliding. Ice is slippery when wet, so for many, perhaps the real question, is why doesn’t ice flow faster! That’s because glacier flow is resisted by friction at the base of the glacier and at the margins of the glacier.

I’m not sure I understand your question; glaciers may flow faster in their ablation zones because the surface slope is steeper (accumulation zones are often rather flat) or perhaps they have less resistance from the valley sides. This page on glacier flow may be useful.

About

I am a Senior Lecturer at Newcastle Univeristy, specialising in glaciology and glacial geology. I wrote and developed the AntarcticGlaciers.org website as part of an ongoing commitment to outreach, education and research impact. Read more about me at www.antarcticglaciers.org/bethan-davies.

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