IMPORTANT - Moving Boulder in Thrupe Lane Swallet

WARNING

Thrupe Lane Swallet.

At the top of Butts' Chamber there is a huge boulder weighing several tons just to the right of the climb up into Upper Butts' Chamber, it is sitting at the top of the steep boulder slope of Butts' Chamber and leaning against the roof.

The moving boulder is indicated by the yellow arrow

This boulder has in the last couple of months moved approximately 40mm. The most likely cause is infill beneath it being washed out by the more severe flood events that Thrupe Lane Swallet experiences. If the process continues it may result in the whole boulder slope collapsing along with the boulder towards and blocking the connection to Bridge Rift. It is strongly advised to avoid the area until further assessment and if possible any remedial action has been taken. The wall Atlas diggers built to stabilise the perched boulders above the wall is not the cause of the huge boulder moving but has fortunately brought it to our attention.

Note that this will affect any Hobnail/Thrupe Lane Swallet trips and any planned visits to Marble Streamway via Butts' Chamber/Marble Chamber.

A warning sign has been placed in the cave

Dave King 21/04/2025