Imagine it’s early 2017, and you’re walking up a steep, winding path in Costa Rica, the surrounding trees dripping water on you with every step you take.
The correct term is cloud forest, and you can see why, because it’s a great deal of both. Fog clings to the twisted branches, sluggish down here, moving fast above the treetops far overhead. A ten-minute walk downslope behind you, the trees have thinned enough to let in the midday sun, which is bright and cheerful - but up here it’s gloomy, cool and slippery underfoot.
It’s also dishearteningly twisty. It’s hard walking like this, where you perpetually can’t see round the next bend. It just keeps replicating itself, like you’re stuck on some naturally occurring Mobius strip and you’re never going to get anywhere...
But suddenly the view opens up, and you see you’re finally somewhere - a huge lake with blue-green water, cold-looking and beautiful and surrounded by silent, densely-matted forest. If it wasn’t so cloudy, you can imagine sneaking past that Closed For Maintenance sign and going for a sneaky swim in its enticingly jade waters. This would be a very bad idea (the signs are there for a reason) - but it’s certainly a peaceful view that is giving you no hint of its ultra-violent origins.
Go back nearly 10,000 years, and this whole view would be a roaring inferno, the kind that would make Dante flinch. You wouldn’t even have got this close. There’s just no way.
Botos is the old crater for Poás, one of Costa Rica’s most impressive volcanoes. You wouldn’t think it, seeing it like this. It doesn’t take long for Costa Rica’s astoundingly prolific plant life to reclaim a mountaintop devastated by volcanic eruption. It’s shockingly fast and it knits itself back together tightly: the hillsides of the country’s Central Highlands are rarely bare, except when cleared to plant coffee, which prefers slightly acidic volcanic soil. Now this scene is just an impressive lakeside view.
But that’s nothing compared with the volcano’s new crater.
A twenty minute walk from here, you reach a boundary where the forest disappears. It doesn’t thin - it just stops, as if scraped right off the mountainside. Beyond it is a vast scoop of rock and earth, and at its centre, far below you, is the evil twin of lake Botos, an eerie milky-green lake of water, pouring white smoke into the air.
Your photographs will forever fail to capture the scale of what you’re looking at. But even here in person, your eyes are fooled. It looks like you could stroll down that slope and be at the edge of that lake in minutes. In fact, the other side of the crater is nearly 2 kilometres away – and once you got to the water’s edge, your shoes would be smoking. It’s one of the most acidic lakes on the planet. Its extreme depths are made of liquid sulphur.
As you watch, steam puffs high into the air.
“Oh, it’s fine,” says someone behind you. “Poás is perfectly safe.”
The last time Poás erupted was 1953, but its destabilizing effect on the region regularly cause small earthquakes. Not today, though. It couldn’t look more tranquil. The sun is out, the National Park is open, and tourists like you are pressed up against the fences of the viewing gallery, holding their phones aloft to rise above the scrum.
It’s relaxed, up here. There’s a faint smell of sulphur now and again, and a cat’s-hair brush of rain as wet clouds from the Caribbean side of the country whip up and over the volcano. It feels like a good place to linger. Alas, you’ll have to leave soon, homeward bound for where you’re staying a few hours away.
But let’s say you could find a way to stay...
After maybe a week, you’d see a marked change. More National Park officials, less tourists. Then the fences and ropes would go up, and finally, the entrance gate. Poás is now closed. Something’s awry with the toxic gases billowing out of the crater. Tremors shake the ground underfoot...
Then, one day in April, just a few weeks after your visit, a sudden explosion will blast steam and rock into the air, to the height of a full kilometre. When the dust clears, the lake will be gone, leaving nothing but a vast, ragged hole, plunging straight down into the rock.
After decades asleep, Poás is once again active.
When I first arrived in Costa Rica in early 2017, I immediately wanted to know about the volcanoes. Being British, I had no experience of them - not the recently active kind, anyway (our most recent eruption was an unimaginable 55 million years ago). What was it like, to live near a mountain that could explode into life at any time? Wasn’t it, you know, scary?
My Costa Rican partner and her family couldn’t answer this. For them, volcanoes were just a fact of life, like a sea that could whip up into a storm at any time, or a sky that could roar a hurricane down on you. (Incidentally, the latter example is yet another of Costa Rica’s environmental blessings: despite bordering the end of the “Hurricane Alley” that curls storms up into Florida and beyond, Costa Rica is geographically well-protected).
I might as well have asked them, “is it safe going outdoors?”
Costa Ricans are some of the most experienced eruption-neighbours in the world: there are currently 6 active volcanoes in the country (now including Poás, woken from its slumber), and 61 dormant or fully extinct craters. Prior to my arrival, another mountain was active enough to be sending smoke high into the sky, and down in the valley containing the capital city, San Jose, my partner had to wipe the windows of her house every day with a wet cloth to stop them getting coated with ash.
When an eruption’s going on somewhere nearby, you might smell it in the air, or even feel it tickle the back of your throat. And maybe you’ll feel an earth tremor or two. But to Costa Ricans, it’s as humdrum as hearing the sound of an aircraft if you’re living on the flight-path of a local airport. An occasional irritation, but that’s about it.
But isn’t it dangerous? I insisted.
In the sense I was trying to ask? Nope. It’s not dangerous at all. Fun fact: statistically, it’s eight times more risky taking a bath! (It’s worth noting that “volcano tourism”, the act of deliberately seeking out erupting volcanoes to visit, is a whole other matter.)
In this case, it’s safe because the volcanologists of Costa Rica have studied its volcanoes for decades. They’ll know when something bad is brewing, in exactly the same way that they knew something was wrong with Poás. Despite the drama of many Hollywood disaster movies, an erupting volcano spends weeks, months and sometimes even years giving off telltale signs of escalating activity. The clusters of small earthquakes, growing stronger. The changes in the gases emitted. The ground slowly shifting.
(Even history’s most famous volcanic horror-stories aren’t as alarming as they first look: the eruption of Vesuvius that levelled Pompeii, for example, was heralded by days and possibly weeks of earth tremors and other signs. Arguably, what really caused so much loss of life at Pompeii and Herculanium was its inhabitants’ refusal to listen to what the mountain was telling them, right to the last moment.)
Nowadays, of course, volcanology is a true science. It’s not a perfect predictor of what will happen - but it is highly advanced and reliable. When Nature decides it’s time for a bit of furniture-rearranging, it usually begins doing so at a speed that you can comfortably outwalk, so you’re safely elsewhere when the dramatic stuff happens. Volcanology is there to tell you when to start walking.
If you walked that same cloud-forested path winding up Poás today, you’d see a few changes. A few more safety measures, a few more signs. And the crater lake is back, as eerie and acidic as ever. But beyond that, and despite everything that’s happened since, it’s not much different to what I saw that day in 2017.
As the country opens up again after the pandemic, tens of thousands of Ticos (Costa Ricans) will be climbing in their cars to see their most famous geographical features up close. And if any of them are feeling a little nervous, I hope they’ll hear someone behind them say “Oh it’s fine. Follow the rules, obey the signs and you’ll be perfectly safe.”
They might not immediately believe it - but it’s the best answer they could get.