Hölloch

Useful Information

Location:	Hinterthal in the Muotatal (Mouta valley), near Schwyz.
Open:	Touristic visit: JUN to SEP Wed-Sun 10, 13, 15:30. A Wasserdom: NOV to MAR daily at day after appointment. B Schlange: NOV to MAR daily at day after appointment. C Glitzertor: NOV to MAR daily at night after appointment. D Parcours: all year daily at day after appointment. E Biwaktour: NOV to MAR daily at day after appointment. F Spezial: NOV to MAR daily at day after appointment. [2006]
Fee:	Touristic visit: Adults CHF 20, Children (0-15) CHF 10. A Wasserdom: Adults CHF 159, Teenager (16-19) CHF 98, Children (10-15) CHF 78. B Schlange: Adults CHF 179, Teenager (16-19) CHF 108, Children (10-15) CHF 88. C Glitzertor: Adults CHF 199, Teenager (16-19) CHF 118. D Parcours: Adults CHF 98, Teenager (16-19) CHF 78, Children (10-15) CHF 48. E Biwaktour: Adults CHF 395, Teenager (16-19) CHF 275, Children (10-15) CHF 195. F Spezial: Adults CHF 239, Teenager (16-19) CHF 148. [2006]
Classification:	Karst cave river cave, cave system.
Light:	none, carbide lamps and headlamps provided..
Dimension:	Length=193,000 m, Depth=872 m, T=6 °C..
Guided tours:	A Wasserdom: D=7 h. B Schlange: D=9 h. C Glitzertor: D=11 h. D Parcours: D=4 h. E Biwaktour: D=2days. F Spezial: D=12-14 h.
Photography:
Accessibility:
Bibliography:	Urs Möckli (2000): Hölloch, AS Verlag & Buchkonzept AG, Zürich; ISBN: 3905111470. amazon.de Alfred Bögli (1965): Im Banne der großen Höhle, Spectrum Verlag Stuttgart, 154pp. () Urs Möckli, Hg. (2000): Hölloch - Naturwunder im Muotatal, Zürich, 2000.
Address:	Führerhaus H. Suter, 6437 Hinterthal, Tel: +41-43-471208. Alpinschule Tödi GmbH, Kirchhaldenstr. 25b, CH- 8722 Kaltbrunn, Tel: +41-55-283-4382, Fax: +41-55-283-4385. E-mail: Trekking Team AG, Lützelaustrasse 48, 6353 Weggis, Tel: +41-848-808-007, Tel: +41-41-390-4040, Fax: +41-41-390-4039, Cell +41-79-420-77-77. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1875	discovered by the Bergbauer (farmer) Alois Ulrich.
1900	development works by a Belgian-Swiss corporation cost 1 Mio Gold Franks.
1904	surveyed length: 4 km.
1909	Belgian-Swiss corporation failed because of too little visitors.
1910	paths and electric light destroyed by a flood.
1945	modern exploration by Professor Alfred Bögli and other speleologists.
1952	surveyed length: 25 km.
AUG-1952	Alfred Bögli and three companions trapped by a flood.
1966	surveyed length: 85 km.
1995	surveyed length: 170 km.
1995	bought by the Draganits brothers.

Description

passage with remains of the old electric light system.

The Hölloch is at the moment surveyed for about 193 km and is thus the longest cave system in Europe and the World 4th largest cave in the world! It is situated in the Muotatal, a karst area with about 20 km². The lower level is a river cave. The oldest parts of the cave system are about one million years old.

This cave was discovered rather late, in 1875, by Alois Ulrich. He was working on an Alp, the typical Swiss high pastries. On his way down into the valley, to his farm, he had to cross a deep abd dry ravine. He did this many times over the years, and normally it was no problem, but sometimes the dry ravine was water-filled. It was impossible to cross the water, but he followed the ravine uphill, and at some point the water vanished, and he was able to cross. When he became older, he thought about it: there was a place where the water emerged from the rock, in enormous amounts. This is only possible if there is a cave, which allows a lot of water to flow through. He searched a while and then found the so-called natural entrance.

During the next decades the cave was explored and finally, at the turn of the century about four kilometers were known and surveyed. The name was given to the cave by the discoverer, he said the cave was "hel", which is a local dialect term and means slippery. So what he really said, was that the cave was slippery, but the German explores thought it meant hell, and so the cave was named Hölloch (hellhole) in literature and the name was born.

cave explorer at the ceiling of a high chamber.

In 1900 a Belgian-Swiss corporation started a large scale development of the cave for tourist use. They built the Hôtel des Grottes in the little village Hinterthal. A path was built from the hotel up the dry ravine to the cave entrance, which crosses the ravine several times on bridges. In the cave concrete paths, stairs, and electric light were installed, a siphon was blocked by a concrete wall. Several tunnels were built to avoid dangerous parts of the cave. They also planned a railroad inside the cave for the following years.

But the railroad was never build. The number of visitors was much lower than expected, only few tourists travelled into this remote valley to see the cave. The income did not match the enormous investments, and after a few years the company was ruined. Only one year after the closure, the several metre thick wall at the siphon was destroyed in a flood, and most of the electric system too.

The cave was never reopened as a show cave, and remained almost untouched for decades. The cave was rediscovered by the young geologist Alfred Bögli in 1945, at the end of World War II. He revived scientific exploration and extended the cave significantly. In August 1952 Alfred Bögli and three companions were trapped by a flood. They had to wait for 10 days until the water level sank, and they were able to pass the siphon. At the end of their imprisonment they were some kilo lighter but famous. Radio and newspapers published all details of several rescue operations. Alfred Bögli wrote a very interesting book about this 10 days inside the Hölloch (Im Banne der großen Höhle, see bibliography above). The best time for visiting the Hölloch is obviously in winter, because there is a much lower risk of floods.

Today there are numerous guided tours into the Hölloch by different operators. There is a touristic trip of 1.5 hours, which shows the more or less developed entrance part of the cave. But the Hölloch is famous for numerous cave trekking trips. The trips differ in length (four hours to two days) and difficulty. They are organized by the Alpinschule Tödi GmbH and by the Trekking-Team AG, see links below. There is also an interesting surface tour showing the karst features above the cave.

This page is about the show cave, which means the tourist tour called Kurzführung. It is offered all year, three times a day, and does not require booking. The visitor meet ten minutes before the trip at the ticket office, only 50 m form the old cave hotel. The visitors are introduced into the cave with a complete map of the 191 km of the cave, which covers two walls of the room. The other walls show pictures of various floods. During a flood the cave fills up to the show cave entrance, and 10 to 15 m³ of water per second rush out of the entrance. In summer 2005 there was an extraordinary flood, said to have been the biggest flood of the millennium. It also affected the cave, with a peak yield of 20 cubic meters through the entrance door. The witnesses described it as a rectangular beam of water out of the door.

Obviously the water influences the tour. Floods are possible all over the year, but mostly they happen in spring. They may restrict the tours or make them impossible. During times of snow melt or very high precipitation, an advance call or an email are advisable. Tours are made, even if not the whole trail is dry, but it may not be able to visit all passages.

We had the luck to visit the cave at high water. The path was closed by water half down the main passage. The luck was not the fact to miss half of the cave, but the way how the closed passage made sounds. Approaching the almost closed siphon we heard a roaring noise. First it sounded like a subway train, then like a watermill. When we finally reached the siphon we heard a deep roaring noise with a slow rythm, about two beats per second. The water filled the passage except for a 20 cm wide and 10 cm high gap at the ceiling. The huge cave system behind the siphon had a different air pressure than in front, and so air was blowing through that small hole. The air current produced waves which closed the hole, and the constant rhythm of waves combined with the airstream produced a sounde similar to a didgeridoo. The sound was extremely loud and bounced off the walls of the passage. An impressive experience.

There are a few more details we can add, but they are less impressive scientific stuff. This sound is extremely rare, it happens only at a certain water level. If the water was 20 m higher, the siphon would have been closed completely, without air current and sound. If the water level was 20 cm lower, there would have been enough room for the air to flow, and there would have been no sound. And obviously the existance of the air current is important. There are various reasons for air currents in caves, but the amount depends on the size of the cave. The Hölloch is really huge, and so there is the possibility for heavy wind. The wind is produced by different pressures. One explanation is the change of the air pressure outside, caused by the weather. There was bad weather outside, but it went better, which is always connected with a rise of air pressure. Another possible effect is the change of the water level. The flood was ending, water level going down, formerly water filled passages becoming dry. The air had to flow into the cave, and because of the size of the cave system, the amount was rather high.

Now finally a few words on the cave itself, at least on the small show cave part. Being a river cave, subject to various floods, the cave has no speleothems. The only speleothems were brought in form Beatushöhle, just to be able to show visitors a stalagmite and a stalactite. The cave walls are slanted, as the limestone was folded by the Alpine orogeny and the layers are now almost vertical. The path was mostly cot out of the bedrock, there are even two tunnels, one for the entrance, and a second one which spirals down from the higher end of a steep chamber to the middle. The path goues up and down very often so visitor should be fit enough able to handle those descentd and ascents. The floor is sometimes a little rough, there may be sand, clay, rubbles and even passages which have flooded floors. Sturdy shoes are required, rubber boots are probably even better. The cave is very cold and wet, warm clothes, preferably fleece pullovers, are essential. There is no light, although the china insulators of the historic light still exist. Visitors are equipped with carbide lamps, children get less difficult headlamps.

The cave walls are mostly limestones with frequent calcite fissures. The fissures are a result of the tectonic stress during the orogeny. Fractures in the rock were healed by calcite. And several layers of the rocks also contain a huge amount of fossils, especially various kinds of brachiopods.

Hölloch Gallery