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Tuesday, 17 June 2014

Short-term high-intensity events -- Isle of Lewis


Those winter storms again..... last winter, as we all know, Britain was battered by some pretty exceptional storms.  Some of the worst were in the month of January.  At that time of year the Isle of Lewis gets 15m swells coming in from the west, but this year the storm waves must have been incredible.......  windspeeds of over 120 mph were recorded.

The two photos above (both from the NW coast of Lewis) show what these storms have done to the landscape, in addirion to many rockfalls and rearrangements of the cliffs.

The top photo shows clifftop damage about 25m above sea level.  Waves have come over the top here, and have stripped away the turf, exposing gravelly sediments beneath.  This damage was not just done by salt spray, but by powerful cascades of water.

The lower photo shows the top of a storm beach in a little embayment, with fresh erosion into a fill of glacial sediments.  The most interesting thing is the large boulder in the centre of the photo -- almost a tonne in weight, and resting on the turf.  That was some wave, strong enough to pick it up and roll it over the clifftop.....  On the right of the photo you can see more serious damage, where the waves have stripped away the turf.

2 comments:

Dave Maynard said...

So, is the sea or the ice the more powerful force?

Dave

BRIAN JOHN said...

Dave -- it all depends where you are!