Saturday, 24 April 2010

Cascade Aven Series DYO - The Ascent of Man

Beside the start of the Green Canal a significant inlet cascades down an impressive high aven that rises well above the height of Cloud Chamber. This was climbed by the original cave explorers to find the stream issuing from an impenetrable bedding plane. Above this bedding plane are layers of lower quality limestone, in which it was thought that no significant cave would form. This high level area of the cave was therefore left unexplored until two years ago Richard Frost, a local caver with a great aptitude for climbing, decided to take a second look. 
After re-climbing the aven at the top of the cascade Richard found that it would be possible to clear enough silt from the bedding plane to make it negotiable by the slimmer caver. Several digging trips allowed the bedding plane to be passed to find a boulder choke that led into the bottom of an impressive chamber, and so the Cascade Aven Series was discovered.
Richard had invited Brendan to photograph these passages and was joined by Chris to explore these extensions to Dan Yr Ogof. Unusually for a trip in Wales we packed our SRT kits and met Richard on the DYO car park at lunchtime, after he had finished a shift at work. Richard took a body sized tackle bag out of his van and packed the camera box in it along with his SRT kit, ladder etc, which left Chris and Brendan to just take in personal SRT kits. Water was very low in the cave after a long period without rain, and we made fast progress to Cloud Chamber, picking up ropes and digging equipment on the way in. We kitted up in SRT gear, and then made our way to the bottom of the cascade, which Richard free-climbed, taking a rope with him. This rope was then rigged down the cascade to act as a handline for Chris and myself to make the ascent.
At the top of the cascade you find yourself at the bottom of an aven with the spray of the stream showering down on you. A prussik up the 30 foot pitch brought us to a ledge where the stream issued from a low bedding plane. A flat out wriggle ensued through the duck to follow the bedding plane, the water soon became less deep, but the flat out crawl contained lots of silt and gravel. This in many ways reminded me of Redhouse Lane Swallet, as we pushed the gravel to the sides of the passage to make progress. Once through the bedding crawl an interesting maneuver was required to pass a hairpin bend that led into the bottom of the boulder choke. Emerging from the choke we found ourselves in an impressive tall chamber, perhaps 30m high in places. 


Richard Frost in the chamber at the bottom of the second pitch.


Richard Frost on a large fallen slab that dominates this chamber.

Chris Webb watching Richard Frost ascend the second pitch.

Photos were taken in this area before we made our way up the second pitch that drops into the far end of the chamber. At the top of this pitch, the water issues from a tight rift making getting off the rope a little tricky. Once clear of the pitch head the stream was followed to a short free-climb into a small chamber at the bottom of the third pitch. 

Richard makes his way to the bottom of the third pitch.

This short pitch was up sharp and loose rock and entered an area of very loose rocks. In this area of the cave there are a multitude of passages leading to loose avens and another short pitch upwards. We spent a little time exploring an unfinished lead that ran off from the final aven. After several minutes of attacking a tight squeeze with a lump hammer, Brendan managed to squeeze through to enter a tall rift chamber. Richard then came through to climb the rift, only to find it closed down too tight at the top. With another lead closed down, we made our exit from the cave.



Present: Chris Webb, Richard Frost and Brendan Marris

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