A rich cave system that is exciting to discover with the help of a guide or on your own if you are used to caves.
The mountains around lake Överuman form one of Sweden’s richest cave regions. The caves were not discovered and studied until the late 1960s. At Kåtaviken, 45 km from Hemavan, there is a particularly attractive cave district. A 4-km trail connects a number of the most interesting ones. The cave trail shows the cave types and karst formations (dissolution formations in limestone) which are typical of the Överuman area. The hiking trail is easy to walk and requires no special equipment.
Things to think about when visiting caves:
• For your own safety and to get the most out of your cave visit,
we recommend a guided tour.
If you nevertheless make your visit independently, remember the following:
• Visiting caves requires strong lamps, at least three to every group.
Robust clothing and safety helmets are also recommended.
• Never go into a cave alone!
• All visits to caves are at your own risk!
2. Limestone and karst
The bedrock of the mountain slope at Kåtaviken consists largely of limestone. This limestone, here changed during the folding of the mountain chain 400 million years ago, is a type of rock which is broken down by water with high carbon dioxide content and by humic acid. Cracks and seams are enlarged, and watercourses running in over limestone bedrock often produce underground flows along these. The cracks gradually enlarge to form caves. An area of limestone bedrock with underground watercourses, caves and other dissolution formations is called a karst area.
Potholes are more or less funnel-shaped holes or hollows in the ground, and are common in karst areas. If the pothole results from a part of the cave system having fallen in, it is called a sinkhole and may form the entrance to the cave. Dissolution pot-holes are formed as a result of subsidence of the soil surface. Water drains down and enlarges cracks in the bedrock. Material is transported down from the surface via these cracks, whereupon the ground sinks inwards. In mountain regions, snow and ice are important factors in the formation of dissolution pot-holes.
4. Outlet cave at Västra Jordbäcken brook
The brook which emerges here from its underground channel via the small arched-shaped cave is called Västra Jordbäcken. In Norway the name describes precisely a stream which flows underground. This outlet cave and its inlet at Forshallarna were discovered in 1966 by a couple of cave researchers from Malmö. This discovery served as a trigger for the discovery and investigation of other karst areas in the Tärnafjällen mountains.
Forshallarna (literally the “halls of streams”) is the name given to the Västra Jordbäcken brook’s inlet cave, and it is here that the brook’s water finds its way underground. This happens when the brook has passed over hard rock types and comes into contact with the limestone bedrock. The water has then enlarged cracks and seams in the rock and formed an underground cave system of unknown size. The water follows the limestone’s westward extension to re-emerge at the outlet into the Västra Jordbäcken brook. Below the great inlet cave one still sees clearly the brook’s old and now abandoned groove. Risk of rockfall! Don’t touch walls or roof!
6. The White tunnel
A fossilised - i.e. not water-bearing - erosion tunnel. The cave has a smaller chamber (A) in the western part and a 16-metre long and narrowing passage to the east. This is remarkable because it is neither an inlet nor an outlet. In principle it is an enlarged crack which became revealed because the western part collapsed. In other words the inlet hole (B) can be said to be a sinkhole. The cave derives its name from the artistically fashioned walls in light pastel shades.
7. The Östra Jordbäcken brook cave
The Östra Jordbäcken brook cave totals more than 400 metres long and is the biggest cave in the area by both length and volume. It forms part of the Jordbäckarna brooks’ drainage system and leads off part of the water from the eastern Jordbäcken brook underground, to emerge again at the Västra Jordbäcken outlet cave. Narrow passages formed by cracks afford access to the cave, leading eventually into a steeply sloping cave tunnel about 100 metres long, 10 metres wide and up to 5 metres high. When the brook water is high, it rushes over the huge mass of boulders on the floor of the tunnel.
Furthest down into the interior the cave descends sharply to a small lake - a water trap or siphon preventing further penetration of the passages between this cave and the outlet cave of the Västra Jordbäcken brook. Getting down and up through the big cave tunnel is demanding, since it necessitates climbing over wet and slippery boulders. Risk of rockfall! Do not touch walls or roof in the cave!
8. Stupgrottan (the Precipice cave)
The cave was formed in what was once a waterfall in the period when the most recent inland ice was melting. The steeply descending 7-metre long cave passageway expands further down into a spacious cave chamber. The cave’s bottom gradient follows the slope of the limestone layer into the mountain. There are several extended limestone cracks at the side of the Döda Fallet (= the Dead Waterfall). These often take very strange and beautiful forms. They are formed by water coursing over the limestone slabs. Another name for these forms is karren.
9. Döda Fallet (The Dead Waterfall)
This is a waterfall, now dried up, which still carries water occasionally during the thawing season. Waterfalls like this were formed by vast quantities of meltwater produced by the melting of the most recent inland ice. They were reactivated during subsequent cold periods when the glaciers of Mjölkfjället mountain were much more widespread than today. The continuation of the former brook can be followed down into the birch forest as a dry channel. There are several small limestone caves at the western end of the Döda Fallet waterfall.
10. Korkskruvsgrottan (The Corkscrew cave)
At 225 metres the Corkscrew cave is the second longest cave in the area. Climbing down it is a very risky undertaking because of loose-lying boulders. The risk of collapse is high, so exercise extreme caution! A little way down, the cave opens out into large chambers with roof heights of 4–5 m. A low passageway beyond the first chambers leads into a chamber 12 m high. The inner parts are usually water-bearing. However, it is not the present small brook that has formed the cave but earlier powerful flows of water associated with the most recent melting of the inland ice. It is difficult to find your way round the cave down here! The beautiful U-shaped valley outside the cave is a so-called glacier mill also owing its origin to the melting away of the most recent inland ice. The Kåtaviken cave trail now ends and you return to the Kåtaviken homestead by the same route as you came.
The path straight ahead goes to the Mjölkbäcken brook cave system, 3 km, and down to the Mjölkbäcken brook homestead on the E12 road, 8 km.