29 January 2021
An interesting example of coastal erosion at Happisburgh in Norfolk
Large parts of the coastal cliffs in the county of Norfolk, in eastern England, are subject to rapid (and accelerating) rates of erosion. The very weak materials offer low resistance to the remorseless attack of the North Sea waves. As storminess increases, and the sea level rises, naturally high rates of erosion are accelerating.
Last week a major storm system, Storm Christoph, passed across the United Kingdom, bringing heavy rainfall and strong winds. Landslides were triggered in a number of locations, including on the railway network (a problem that I have described previously). Close to the town of Happisburgh in Norfolk an interesting erosional feature has developed on the coastal cliffs.
The image below has been tweeted by several people (the source is unclear to me, possibly Getty Images). It is a very clear illustration of the erosion – and note the person on a bicycle for scale:-
Technically, this is probably an erosion event rather than a conventional landslide. My interpretation is that the rainfall intensity exceeded the infiltration capacity of the soil in the field, generating overland flow. This has found a small topographic dip in the cliffs, driving the generation of a channel. From this point onwards it has allowed the flow to intensify and downcut, and then to drive retrogressive erosion. There will have been multiple small slope failures contributing to this process both on the cliff line and within the retrogressive bowl as the water drove undercutting.
Of course this will now drive a rapid setback of the cliffs in this area of the Happisburgh coastline in future storm events. Unfortunately the farmer is likely to lose a substantial amount of land.