Castle Rock, St John’s, Cumbria

Castle Rock Instability – Update May 2015

Summary: The crack continues to widen with clear evidence of debris falling out from it (i.e. stone-fall danger). There is every indication that this collapse is going to take place sooner rather than later.

Detail: The crack is progressively, continuously, rapidly widening relatively speaking with quite a bit of loose debris falling into or out of it. A stone dropped down the back of the crack – reveals how hollow it is. The crack, particularly above and left of Matheson Avenue is perceptibly much wider and very active. Similarly the crack at the crag top is perceptibly wider and quite active as is the crack’s extension down southwest towards the finish of Overhanging Bastion this is very obvious when viewed from above.

A gauge is in place measuring the movement; the results for this are shown on the graphs.

The crack line and estimated fall zone are shown above (The right end of the North Crag is beside the right hand X

You can see from the plot that we are currently undergoing the fourth seasonal perturbation. Between April and June each year the motion of the movement changes, probably due to more intense sunlight, warmth or seasonal drying out.

There is every indication that this collapse is going to take place sooner rather than later. A local earthquake might do it, recently there have been three (May 22 – Dumfries,

May 14 – Coniston, May 11 – Dumfries and Morecambe Bay). This is very unpredictable however. Personally I am starting to be wary of walking under the North Crag!

On a lighter note, the suspect section of rock may slip and come to rest at an easier angle so that North Crag Eliminate falls to VS before it falls to the bottom of the crag!

From notes provided to Trevor Langhorne.