The Volcano Adventures – Lava caving

I love caving. I love the dark, damp, unpleasant places beneath the world, the “primordial tunnels in perpetual darkness”. I’m starting to struggle with the physical aspects of climbing and crawling and hauling myself through awkward squeezes but I’m still very much of a fan of the cave.

So when I went to Iceland and the opportunity came up to go lava caving, I had to try it.

Caves in the UK are overwhelmingly limestone caves, where water action has carved out twisting passages and calcite has formed decorations. I still have a great fondness for the smell of wet limestone. In Iceland, on the other hand, the caves are mostly made from lava, where a flowing river of molten rock has solidified on top, leaving an underground river which eventually drains away to form tube-shaped caves.

Leiðarendi is a smallish cave system just outside Hafnarfjörður. I’ve only ever been there in the snow and I know I could never find it by myself in a frozen white nothingness. You leave the minibus by the side of the road – a road that’s barely distinguishable from the wilderness – and then you hike through the snow to the entrances.


I’ve never been there in summer but apparently this place where I’m sprawled elegantly in the snow is kind of a crater the rest of the year. That’s probably right because I know the entrances – there are two, the other one is out of shot, on the right – do have a bit of a snow climb before you hit actual cave.



I’ve done this trip twice – once with Iceland Excursions/Greyline and once with Extreme Iceland and I’m going to go right ahead and recommend Greyline. For one thing, they provide bright orange overalls and actual headlights and for another, they don’t go actively encouraging you to break off icicles and write your name in the slime on the walls. I know the icicles will grow back next year but it’s still vandalism and kids won’t understand why it’s ok to break off ice but not to break off rock and as for writing in the slime – well, if your name is still there twenty years later (our guide showed us where she wrote her name as a kid, so it’s there forever) then that is unforgivably bad, do not do that. I am beyond furious about Extreme Iceland’s “yeah, you go destroy the cave, kids!” attitude and I’m not sponsored for recommending one; I don’t need to be to pick the one that isn’t telling people to deliberately damage the cave.

This is BAD - do NOT do this.
This is BAD – do not do this.

As well as providing better equipment (mind you, my issues with Extreme Iceland’s Maglites are my own – I just find them unwieldy and inefficient as anything other than a blunt trauma weapon), Greyline has better guides. Matthias – the Matthias of the Þórsmörk vs Sandals debate – took us down into the dark, sat us down and told stories in the dark, stories in which I became the eager kid who tried to answer all the questions (“Why don’t trolls come out of their caves during the day?” “They burn!” “…. that’s vampires.” I did get it right – they turn to stone – when I gave it a moment’s thought and no one else in the group even tried to answer). I will always fall for sitting in the dark – I still regard it as an essential ritual, if for no other reason than to let your eyes adjust to the dark before you get going properly and I will love you forever if you add stories to that ritual.


So, Leiðarendi means “end of the road” which refers to the fate of a sheep that strayed inside quite a long time ago. Its skeleton is still in there but I can’t find any pictures of it – which probably isn’t a bad thing. I forget where the entrance is on this survey but I’m pretty sure it’s somewhere in the middle and when you’ve done one half of the cave, you can go and do the other if you really want to.

The first thing I noticed – other than that the rock is mostly dark red rather than mid-brown like limestone caves – was the icicles. I broke so many of them and I felt so guilty about it. Knocking your head on them because your helmet is restricting your vision a little bit isn’t the same as deliberately snapping them off for the fun of it but it’s still not a good thing to do and I was making a lot more effort not to crash into them without anywhere near the success rate of everyone else. Falling icicles make quite a tinkle, it sounds like breaking glass and that increases the guilt for smashing them.



I spent so long trying to capture those glittering icicles that I didn’t get any pictures of the nature of the caves themselves, that they’re tubes. I think this one is the best I’ve got and it’s not even in focus.


The thing that surprised me about the lava caves was how similar they are to limestone cave. They may have been formed very differently but in the four thousand years since the lava drained out of Leiðarendi, things have happened. Pieces of rock have fallen from the ceiling, making little piles of boulders all over the place.


Flowing lava, working a bit like water erosion (at least, I assume that’s what’s happened here) has left horizontal lines across banks of rock here – in limestone caves, this is where you can really see water action and I hadn’t expected to see similar evidence in lava.


But the thing that really surprised me was that there are formations. Stalactites, stalagmites, bacon curtains etc. This bewildered me for a while – are they also the result of water-soluble minerals? Is there calcite in lava? What is lava actually made from? The internet has since told me – and I’m still only half-convinced by this – that the formations are formed by half-set lava dripping, that rather than these stals being formed over hundreds of thousands of years, they’ve formed in weeks or days or even hours.





I still don’t know what’s going on here:


I know it’s a hard sell, convincing people that it’s fun to crawl around holes in the ground so I’m not even going to bother. Just, if you’re already one of those people who enjoys it, go and see what the Icelandic lava caves are like.