Wednesday, July 18, 2018

Caverne de Saint-Léonard

I had a free afternoon on an otherwise busy business trip in Montreal, and I wanted to visit Caverne de Saint-Léonard, a famous cave right under a city park. While this is a small cave, what I found was not your typical touristy show cave, but an adventure.

This was not a stroll on an asphalt path with handrails. We went on all fours, climbed ladders, and chimneyd cracks up.

The cave is just 50 meters long, but just last year, in October 2017, they discovered 350 meters more tunnels. On our climb, we got to see the entrance hole to the new parts, with a tempting ladder on the other side taking you down to the virgin cave. Sadly, that part cannot yet be visited. But it is interesting, a crack partially filled with water so it has to be navigated by an inflatable boat.

The opening to the new part:

The cave has been formed when immense pressure from kilometres of ice pressing on rock cracked the rock, a process known as glacial tectonics. In the years after the crack formed, water seeping to the cave has also formed stalactites, but this is not a karst cave.

We also saw some life in the cave, two small crawlers and one all-white (but dead) spider.

More information about the cave, booking of tours, etc can be found on the Quebec's Speleological Society's web page.

More pictures:

Tämä artikkeli löytyy myös suomeksi Relaasta. All caving related articles can be found at and all skiing related articles at

Photos and videos (c) 2018 by Jari Arkko. All rights reserved.

Monday, July 16, 2018

Canadian Heat Wave Snow

I had a great Sunday, starting with work work work, with some progress I think, then went skiing, and finally returned to have a nice sauna and a swim at the hotel. And afterwards met some fun new Argentinians from my meeting at a late reception.

And yes, I did find snow after a long heat wave here in Montreal. Maybe a six meters long stretch, perhaps even as much as seven :-)

Thanks to Patrick Corcoran and Greg Rich who kept me updated on the melt in Saint-Sauveur; thanks!

Photos and videos (c) 2018 by Jari Arkko. All rights reserved. This article has also been published at Teton Gravity Research.

Monday, July 9, 2018

Cave Radios with Bo Lenander

I had an opportunity to interview Bo Lenander, Swedish Speleological Society, about cave electronics and communications equipment. In this video he explains the equipment that he has built and what it can be used for. And then we try it out in the Gotland's Lummelunda cave!

Cave communications equipment and positioning tools have been in the news recently because of the Thailand rescue efforts. Caves are extremely difficult environment for communications, but there exists a few different types of equipment that can provide some form of communication.

These tools are used for both safety and rescue purposes, to inform those waiting above ground on the progress of an exploration party. The party can indicate whether they are proceeding according to plan, are delayed, or need help. And should there be an emergency, knowing the location of the cavers is obviously important.

The tools can also be used to pinpoint where an underground point is. For instance, in the Lummelunda cave, this location finding process has been used to improve the accuracy of the map of this 4-km long cave system. It has also been used to find the correct location to make a drill hole into the cave. (These holes can be used, for instance, to monitor the cave during winter months when a lot of water flows through it.)

Rock absorbs frequencies that we normally use for radio communication. This means that our phones, walkie-talkies and other equipment cannot be used. However, low frequency 1 to 100 Khz magnetic field can be used for communications. For instance 32Khz and 87Khz have been commonly used. Communication is typically possible through several hundred meters of rock.

Bo has built direction finding receivers since 1959, with varying capabilities for range, number of signals, and one- or two-way communication. Bo's paper at the 2017 International Caving Symposium is a description of his most recent equipment (link, paper starting from p. 321).

See also "Signal Seeker", short movie about Bo's dive exploration of the Bjurälven cave (at age 70!) and how they used the radios to locate points within the cave.

There are similar systems elsewhere in the world. British cavers have built many models, including the original "Molephones" and the later "Heyphones". Heyphones were named after their developer, John Hey. Several Heyphones were reportedly shipped to assist the Thailand cave rescue.

More advanced systems have been developed in recent years, and a number of commercial or semi-commercial systems have also appeared on the market. For instance, the Cave-Link system uses suitable radio communications as well as mesh networking among Cave-Link nodes to reach out to far-away distances in a cave.

If you want to know more about cave radios, I can recommend Dave Gibson's book "Cave Radiolocation". Shorter Internet resources include principles of cave radiolocation and the through-the-earth-mine-communications wikipedia article. A good list of all resources can be found from UK caving association's radio communications page.

In our test, here is caver Ralf Strandell with a probe that sends signal through rock:

Bo Lenander searching the cavers underground, using the red, gun-type listening device:

The yellow, square-format high-precision antenna:

Two in-cave probe models:

The entrance lake to the Lummelunda cave:

Lummelunda cave forms:

Above-the-ground tour in Lummelunda by Bo Lenander:

Ralf Strandell in the cave with the probe:

Photos and videos (c) 2018 by Jari Arkko and Jukka Erik Palm. All rights reserved.

Tämä artikkeli löytyy myös suomeksi Relaasta.

Other Planetcaver articles and videos are available at the website. See also the previous articles from Lummelunda, "A Kilometer Inside" (also in Finnish), "On the Beach" (also in Finnish), and "Lummelunda Cavers's Camp". Jukka's articles can be found from the Lumo, a magazine dedicated to nature photography. Finally, Jarmo Ruuth's video about the 2018 Lummelunda camp can be found on on YouTube.

Sunday, July 8, 2018


While at the caver's camp, I felt like I needed a shower... and a sauna. Solbergabadet in Visby to the rescue!

This nice community swimming hall is practically empty during the summer, but offers a 25-meter pool, jumping tower, and good saunas. The saunas are exactly the right temperature, which is a bit surprising for a community saunas and maybe also more generally many saunas in Sweden. But the sauna was decently hot but not too hot. Very nice!

I visited Solbergabadet a couple of times during the week, on almost all days. On one day though I had shower in the camp, using my shower bag that was hanging from a tree, warmed up water during the day. That was nice, too.

It was also fun to watch Ralf (who came with me one day) to swim backwards for cave diving practice. I need to try backwards swimming next time.

Photos (c) 2018 by Jari Arkko and All rights reserved. More sauna-related articles can be found at the website, and stories about swimming at the website.

Camping Sauna

At the Lummelunda campsite, someone had constructed a sauna out of tarp. Rocks would be heated in a nearby fire pit, and then brought inside for the heating of the sauna.

This sauna was not built by those of us in the caving camp, so we didn't get to use it. Would be interesting to try it out though!

Photos (c) 2018 by Jari Arkko. All rights reserved. More sauna-related articles can be found at the website, and stories about swimming at the website.

Saturday, July 7, 2018

Sikalammen luola. Cave of the Pigpond.

Evening exercise, drive to Nuuksio and visit Sikalammen Luola ("Cave of the Pigpond"). I found it, although the forest in the area is difficult going.

This cave is a small roof cave on a cliff, maybe 4-5 meters wide and 2-3 meters deep. Not really a proper cave, but ... this is what we have in Finland!

For some reason there is a brown children's sled in front of the cave.

The coordinates for the cave are N 60.27798 E 24.60321.

Photos (c) 2018 by Jari Arkko. All rights reserved. More caving articles can be found from

Cleaning up rat shit in the cabin

+10C, raining, high winds, cleaning up ratshit in the cabin, a fallen tree on our swimspot... HAPPY MIDSUMMER!!!

All we need now is a hail storm.

Seriously though, this is actually very nice, and the cabin brings many memories. Our sleeping spots in the other cabin are now ready, toilet is operational (although when wouldn't outhouses be?), and we are grilling in the grillhouse. With a bit more cleaning we may get to go to the sauna. And the nature is very beautiful. I feel good in this place.

Photos (c) 2018 by Jari Arkko. All rights reserved.