Sam
30 Aug 2026
A huge rockfall at Holywell Bay has destroyed a Cornish landmark!
On Sunday 30th August 2026 locals and holidaymakers visiting Holywell Bay in north Cornwall were met with a mighty surprise!
A huge rockfall occurred overnight in the cliffs towards the north of the beach. I haven’t seen it in person yet, but looking at the images I would guess that around 20-30 thousand tons of rock has come down. In doing so it has completely obscured the entrance to the famous holy well - a natural spring in a cave. The landslide may have caused the cave itself to collapse as well.
This type of geological event doesn’t always make the news, unless it occurs at a major Cornish landmark like this. In fact, landslides in Cornwall often come as a surprise, compared to some locations along the South Devon and Dorset coasts. But they occur more regularly than you might think.
Whilst the vast majority of the Cornwall’s coastline is made up of hard bedrock like slate and granite, it is still susceptible to coastal erosion. Small rockfalls are common, with a few tons of material coming down every so often. However, once every several years or so we see rockfalls where several hundred thousand tons or more of rock can collapse. These cause dramatic changes to our coastline, with implications on access and safety.
These rockfalls are controlled by two main factors – fractures in the rock, and groundwater.
Firstly, fractures. These discontinuous surfaces are planes of weakness that allow rock to fall apart. They can be tensile joints where the rock has simply cracked open, or faults where adjacent blocks have moved past each other. The frequency, consistency, and orientation of fracture networks all contribute to the susceptibility of a rock mass to fall down.
The presence of water in a rock mass also has a profound effect on its stability. Water can percolate through fractures in the rock, or through the rock itself if it is porous.
Water under pressure (known as hydrostatic pressure) pushes back equally in all directions. So the weight of rock pushing down (known as lithostatic pressure), which usually keeps the rock mass stable, is equally pushed back by the force of water. This decreases normal stress (the direction of force acting perpendicular to a fracture surface) and increases shear stress (the direction of force acting parallel to a fracture surface), The presence of water along fracture surfaces effectively acts as a lubricant.
Knowing this, these cliffs in north Cornwall are quite susceptible to failure in certain circumstances.
Here at Holywell, a combination of low-angle Variscan thrust faults and later, high-angle extensional faults in the Devonian Trendrean Mudstone Formation have created a series of criss-crossing fracture patterns. Some of these are parallel to the coastline, some are perpendicular, which has allowed the sea to carve out caves like the one where the holy well is / was.
Add to this the unique weather we’ve had this summer in Cornwall. It has been very hot and dry, but more recently we have had some very heavy rainfall over the last week or so.
This impacts the rocks in several ways. Dry weather causes the overlying soil and superficial sediments, and the bedrock to contract, increasing the frequency of cracks. Also, because of the dry ground above water fills the cracks faster than the ground can absorb it, increasing hydrostatic pressure along them. Add to this the weight of the ground above, the chance of failure is very rapidly increased. It has created a perfect scenario to increase the likelihood of cliff collapse.
The holy well, only accessible at low tide, was made famous because inside the cave groundwaters had percolated down a fault plane and precipitated out calcareous minerals in to some awesome shapes and colours. It really was a magical place.
It is very sad this historic Cornish landmark may have been lost for good. However, it is an inevitability; nothing lasts forever. I think the sadness comes from the fact these things happen over geological time which is seldom seen within our rapid human lifespan. In our minds the holy well has always been there and it has been taken away from us. We don’t like change, do we! But the fact is the landscape around us is forever evolving.
Whilst I am mourning the loss of this landmark, I am also excited to see the power of our Earth, and how she will every so often remind us that she is bigger than us. She will do what she wants, when she wants, whether we like it or not.
The most important thing though is that this is unlikely to be an isolated occurrence over the next few days and weeks. It is imperative this risk is communicated to beachgoers and coast path walkers, to watch out and stay clear of cliffs, both at the bottom and top!
Keep several metres away from the base of the cliffs. Whilst a hard hat might protect you from the odd little rock that might come loose, it is only likely to preserve your dental records for the coroner if a chunk like this comes down.
If you’re walking the coast path keep at least a couple of metres back from the edge. The cliffs in Cornwall often undercut, so what looks like solid ground might not have anything underneath (think Wile E. Coyote). Also, keep your eye out for any cracks that might appear in the ground. These can be several tens of centimetres wide, and can occur tens of metres away from the cliff edge!
If you witness a major cliff collapse, or if you see any indication a collapse may occur (e.g., large cracks appearing), ensure you are in a safe place and report the hazard either by contacting the Cornwall Council 24-hour emergency line at 0300 1234 222, or by contacting the coastguard by calling 999.
Finally, please don’t read this article and feel you need to rush to Holywell for a photo opportunity. There isn’t much to see any more funnily enough, and the cliffs are still likely to be unsafe following the collapse. I wish you safe and happy exploring elsewhere on the Cornish coast!
Thank you to Kev Hichens for permission to use the cover photo of this article of the cliff collapse.
