Tresviso Caves Project

Tresviso Caves Project Gazetter

T169: Flowerpot

(Sima de la Maceta, Sima del Florero, Torca del Picu Boru)

Area:Pico Boro
East, North:359951, 4786262 (nearby)
Coordinate Quality:GPS
Long, Lat:-4.724255671331, 43.21612616716 (map)
Elevation (m):1785
Length (m):1809
Depth (m):-723
Active Lead:
Survey Available:


On the Eastern slope of Picu de Boru (not the main Pico Boro peak). 100m from the ridge from Northern end of Del Moro depression, scramble up to entrance


5x 3m hole at base of small cliff disguised by foliage Entrance


N.B. all rigging information is based on 80's exploration, using spits and natural rigging.

Short climb down to sloping mud floor and to head of first P25. Bolt gives free hang into large chamber with boulder floor and skeleton. A window in the shaft leads to a parallel pitch to the side of the chamber.
There are two ways on in the chamber floor. Facing away from the pitch, BEN series is left down through boulders. The small opening on the right loads to BILL series.

BEN series:
After the climb down a short crawl leads to a low chamber. Here a passage on the right leads back to BILL series. Straight on to a short crawl and then left to the start of the 2nd pitch of 34m (Teddy's Pitch). Belay around large boulder and down mud slope to calcite boss, descend over calcite to right to bolt. A tape re-belay is useful halfway down pitch. Bottom of pitch is narrow rift, which if followed up widens to smooth floor of aven (unclimbed).
Continue down rift to 4m ladder, then follow the rift and traverse to a climb down, wide passage up to top of 3rd pitch. Bolt in wall opposite large calcite flow, with stal back-up gives free hang of 28m (slight constriction 2/3 way down).
The 4th pitch of 15m is immediately around the corner, with a bolt take off in constricted rift. Pitch opens out to large ledge originally covered in loose boulders. Bolt rebelay at ledge gives 9m pitch into Rock Garden. Pendulum 2m from bottom of rope onto large boulder, which is top of boulder pile. This collapse chamber is the junction with Little Weed cross rift, an impressive vadose canyon. Left from the Rock Garden, the canyon can be traversed upstream at high level for a short way but is unexplored from there.
On right a small chamber, and down a calcite flow leads to top of downstream canyon. Traverse right and climb down 20m. Easy traverse with one wide section to climb down (tape) to stream and head of 8m pitch.

The cave here is pleasantly wide with a large pool. The passage narrows, and traverse over hole in the floor with pool, to top of the easy 6th pitch of 16m (muddy ledge halfway). The wide passage (Paso de la Oveja que come Nesquik) again closes to an awkward take off in the rift for another 16m pitch. A short walk in pleasant passage leads to a very awkward mudstone/shale rift. (The next section was not surveyed).
Traverse up to a dry chamber with old formations. Squeeze through into rift at roof level 25m above stream level. Continue for 40m to a window in circular shaft. Climb up to 15m pitch into pool (Pozo del Lago). Climb over pool into the continuing rift with several small climbs at stream level eventually reaching another shaft of about 40m. The pitch from here is too shattered so slightly back from the pitch climb down 10 m in the meander to where an 8m pitch regains the stream. This time the same 40m shaft, Pozo Critico, is reached partway down and can be safely descended as a 25m pitch.
A smooth-floored balcony above the water makes an ideal campsite for exploration.

The cave continues as a meandering shale rift with several awkward sections to 4m pitch down to a pool with a sandy bank. Beyond, the rift passage gets smaller and smaller, through one tight section and then to flat out tight crawl, with a faint draught Autopista Sangrienta (Bloody Highway). The rift widens before second 4m pitch is met. Staying near roof level above a deep fissure in the floor the end of the meanders opens out to Pozo Comepiedra (Stone-Eater Pitch) The depth of the cave is -350m at this point)
Pozo Comepiedra in an extremely impressive rift up to 20m across with a superb free hanging 54m pitch which lands on a floor that slops steeply downwards to another drop of 17m. Scramble down the boulders until another overhang is reached. This is a broken 24m, (130m total?)
Pozo Flobalop, a 40m deep shaft, is next. At the bottom the stream flows along a high canyon and then sinks into a cross rift. A small hole ahead takes most of the draught and the start of a short oxbow section to an 11m pitch and then a 17m pitch landing back in the water again. A short stream passage ends at the top of a deep shaft, Pozo Slugalug.
Pozo Slugalug marks the end of dry caving in Flowerpot. This damp spray filled 116 m deep shaft is rigged as a series of short drops.
Two more pitches of 15m and 12m and final 6m pitch lands in terminal sump pool. (-723m)
BILL Series
The small opening leads to a chamber with a sloping floor. Down to the left leads back to BEN series, whilst a 3m climb down at the bottom end of the chamber leads to a 20m pitch. A small passage leads to a pitch of 7m into a small chamber, with a minor inlet and straight onto the head of a 40m(?) pitch. At the bottom is another small inlet, and the stream flows into a fissure. Traverse over, to a 10m pitch followed by a 38m pitch Puit Technique Francais. In the chamber at the bottom the water flows down into an inclined fissure, which can be followed for 50m before becoming too tight. No way on.

BEN Series - Boulder Bluff (2018)
Heading left (upstream) from the Rock Garden leads through 15m of easy rift passage to a climb down onto a ledge, halfway up a large shaft, with two small waterfalls entering from above on the opposite side of the chamber. A bolted y-hang gives a clear drop of 25m to a gravel and rock floor, with both waterfalls having merged and sinking through the floor. Turning away from the water, the passage descends and becomes a snaggy crawl for 10m to the head of a 10m pitch. After climbing out of the crawl, the pitch can be rigged on naturals behind you. At the bottom, a horizontal rift can be followed for about 2m before splitting into a downwards and horizontal rift, which are both too tight (10cm wide). This final pitch is completely dry with no draught, the water must take some other route.
On the pitch, 5m above the floor, it is possible to pendulum around a corner on top of a large boulder. This is presumably the bottom of the boulder pile which forms the floor of the Rock Garden. Following the left wall leads to a very short section of rift, and then overlooks a chamber which can be seen from the Little Weed rift. Various other, very loose, gaps up through the boulders can be seen, which are presumed to link back to the Rock Garden.

BEN Series - Aerial Antics (2018)
From the ledge above Boulder Bluff, a 10m bolt traverse over the pitch head, followed by a 10m bolt climb upwards leads to a ledge with a few chocked boulders. Walking 10m around a corner leads to a clean washed 5m high pot containing one of the water streams.

A free climb just back from the corner leads to the top of the pot, where the water enters from 7m above, from what would be a tight squeeze, at the top of a bolt climb.
Behind, traversing and a pendulum over a variety of chocked boulders (up to 5m in diameter) eventually leads to a stance under an impressive false roof. Heading away from the main shaft here leads back to overlook the previous climb.
A bolt traverse around the wall of the main chamber for 6m leads to a pot containing the other stream. This was bolt climbed for 8m to see that the rift the water emerges from is choked with rocks.
Further bolt climbs upwards in the main shaft may be possible, however the vertical/overhanging nature of the shaft above this point would make them very difficult, and no obvious aims/leads were spotted.
BEN Series - Bottom of the Barrel (2018)
An alternative route onwards was discovered from the bottom of Pozo del Lago through a fossil rift passage found at a slightly higher level than the known route.
From the foot of Pozo del Lago a tall rift continues with the stream entering at a low level. The way on is a wide shelf a metre above the floor gives access to a mid-level opening in the rift. Further on in the mid-level the rift bells out to a small chamber with shallow pools of water, and this is the original route on. Above this part of the chamber a layer of dry mud separates the higher level of the rift.
Before the pools of water are reached, routes upward give access to a high level with large shelves of mud suspended in the rift. Traversing the higher-level leads to an inactive upper region. Continued traversing across dry reddish mud leads around a right-hand bend, the mud floor here is probably false. On the right-hand side a short climb up flowstone (with 'draught' scratched into the calcite) into a draughting hole is unexplored. To the left, the floor drops away and a short rift continues coated in loose dry reddish sand, leading to a pitch head. Bottom of the Barrel (10m) drops along a large calcite flow to a mud and crystal floor.
The only way on is a short clean rift passage, which briefly widens into a small chamber with a mud floor, the rift continues to another pitch head. The 6m Tequila Sunset descends a calcite flow to a fine crystal floor. A 2m climb down enters a tall rift coated in calcite popcorn. After a short distance the rift opens into an undescended pitch and falling water can be heard (but may join back into the known system).
BILL Series - Deflowered Chamber (2018)
From the 2nd pitch in BILL series (7m) a tight sideways crawl to the right leads to a new ~15m chamber with impressive stalagmites. The chamber was bolt climbed from a sloping ledge to the left of the stalagmite, up over a flake nose gradually leading left to a small calcite flow. Over the lip, this leads to a ledge about 3x5m where the calcite flow continues across the ledge and up to a hole in the roof from where the flow comes in.
Up to the left of the flow a tiny ledge allows the climber to look into the hole, which appears to continue up with the flow in a tight sloping tube. This seems to be around 20m above the entrance crawl and water dripping into the crawl form the top might suggest a small inlet or connection up there.
BILL Series - 2018 extensions
The 1981 limit of the BILL series was at a -150m at a tight rift. In 2018 an alternative route was found over the too-tight rift.
From the previous limit of exploration, just before the water turns right to sink in the final rift past an awkward pitch head (10m), climb high and continue through a small squeeze.
The squeeze leads to the rift continuation, following the draft through crawling and easy traversing, though small bags could be dropped. Halfway along this 40m of passage, a portcullis of stal columns is bypassed below with ease, this gives the passage its name - Ivory Market. The end of the rift is marked by a change in its nature, as the floor opens below into a large chamber.
A short traverse line and access pitch of 8m leads to the Elephant's Trunk pitch, descending 30m into the chamber below. There is potential for continuation above this pitch head, unexplored. From the chamber, the only way on is 20m of body sized tube, leading to a sharp rift containing Invasive Species, the final pitch of some 70m with 20m of access pitch rigging and traverse above.

Part way down this pitch there is a small inlet window (unexplored). The large flat floor contains a slot that forms a familiarly sized rift Waterway to Spend Sunday, that appears too tight for further progress.


Anon. (1981). "Tresviso 80. An expedition to the Picos de Europa,Northern Spain, 1980". L.U.S.S. Pp. 10-12.
Daykin, K. (1981). "Tresviso '80". Caves & Caving-12:18.
S.E.I.I. (1982). "La Sima del Flower-Pot". Jumar-5:115-117.
Anon. (1981). "Tresviso 1981". Memoria SEII. Inedito.
Daykin, K. (1982). "Tresviso '81". Caves & Caving-15:16-18.
Checkley, D. (1982). "Exploring Flowerpot". En "Tresviso '81". LUSS. Pag. 7.
Anon. (1982). "Cave Descriptions and Surveys". En "Tresviso '81". LUSS. Pp. 17-18.
Sefton, M. (1984). "Cave explorations around Tresviso, Picos de Europa, Northern Spain. Flowerpot". Cave Science vol. 11-4:222-228.
Anon. (1985). "Sima del Florero".