AREA 15: Huoi So

HS1 Can Ho 1

The entrance is a boulder slope underneath a large porch, in which an active river disappears. The underground river can be followed for 500m up to a sump.

HS2 / HS4  Ba Phong 1

From the Da river, follow the tributary that resurges (out of HS2) close to the village of Ba Ba Phong. At the time of out visit this river was dry and could be followed up to the cave through the bed, filled with rounded boulders. The underground passage is sometimes very large (over 50m wide) and filled with huge blocks which allmost reach the ceiling. The cave can be followed up to the sink (HS4).

HS3 Ba Phong 2

Ba Ba Phong is located about 40km to the North of Quynh Nhai along the Da river. The cave can be accessed at the resurgence. Here, several entrances immediately give into a beautiful gallery with a fast flowing river (discharge estimated at 750 l/sec) where shallow and deep passages succeed each other. The walls are polished and there is a small fossil part. Too soon a large sump is reached of which the bottom could not be seen an which is very wide. It would be very interesting to dive this sump.

HS5 Con Ho (Tiger Cave)

The entrance of Co Hon is located a few kilometres upstream of the village Ba Pa Kha along the River Da, about 10m above the water level of the river. The entrance is a few meters wide and high and located below a rock-face. At the time of exploration, the cave was completely dry but during the rainy season water is told to come out of the cave. The river-bed consists out of river pebbles and wet mud. After about 100m of walking and easy crawling the cave seemed to end. Two meters higher a squeeze was found where draft could be felt an bats flew out. The squeeze into soft calcite was hammered and could be passed. Behind the squeeze one arrives in a beautifully decorated part, where after about 130m exploration ended in a small room. Here an impressive flowstone formation goes up, which was not climbed because lack of time.

HS6 Pac Na 2

From the village of Pac Na the Da river was followed upstream for about 2 km where an important tributary is reached. Following this river for about 3 km we reached the foot of the mountains. This is where the water resurges out of different springs. We checked all of them, without succeeding to access the underground river. Above the karstic springs a dry canyon was seen, going into the mountains. After half an hour of climbing in this narrow, steep canyon the small entrance of Pac Na 2 was found, which is a steep boulder slope about 10m above the valley bottom. In a small chamber an 8m pitch gives way to a steep gallery with a rather sporting squeeze, which is followed by a narrow meander. Behind this meander a chaotic boulder chamber is reached, where it’s hard to find one’s way through. Again a small meander was found, with three pebble siphons. The cave gets wider again, but after descending a small pitch it becomes to narrow and no draft could be felt here.