A section of the 67-metre An Branán Mór sea stack at the Cliffs of Moher has broken away and fallen into the Atlantic in a dramatic example of the continuing erosion of the Co Clare coastline.
The change in the well-known sea stack was noticed on Thursday, August 13, while a passenger vessel was sailing beneath the cliffs.
Footage has subsequently emerged showing the moment part of the rock formation broke away and crashed into the sea.
US visitor Melissa Blackburn captured the rockfall from the Cliffs of Moher coastal path above, while Captain Jim Griffin of Doolin Ferry later noticed the resulting change to the stack while sailing below the cliffs.
Atlantic Erosion
An Branán Mór stands approximately 67 metres high and was itself once connected to the main cliff face before coastal erosion isolated it.
The Cliffs of Moher were formed from sandstone, siltstone and shale laid down approximately 320 million years ago during the Carboniferous Period.
Atlantic wave action, wind and weather have subsequently eroded the coastline, producing the caves, arches and sea stacks which characterise the cliffs.
The latest collapse provides a particularly visible example of that process continuing today.
Rockfall Captured From Above
Griffin said the change was immediately apparent because he regularly passes the formation.
“We sail past the sea stack daily, so I immediately noticed that a substantial section had broken away,” he said.
“The rock formation was created by thousands of years of erosion, and that process is still happening before our eyes.”
The rockfall occurred after the main seabird nesting season. An Branán Mór and the adjoining cliffs form part of an important nesting area for seabirds along the Clare coast.
The Cliffs of Moher extend for approximately 14 kilometres and reach 214 metres at their highest point. They form part of the Burren and Cliffs of Moher UNESCO Global Geopark
