After years of dreaming of the Alto Guajira, I am at last setting off with the kids. Except two hours later, we are still stuck in traffic on Bogotá’s Calle 80 with only 12 kilometres on the clock and 1,200 to go.

“Are we nearly there yet? When will we see the sand dunes?” says a small voice from the back seat. “We haven’t left Bogotá, if you hadn’t noticed,” I answer as we inch past a shopping centre.

The fact is, La Guajira is as far north as you can get by car from the capital and still be in Colombia, something underplayed in our pre-trip preparations, watching Youtube videos. This mysterious and far flung badlands of brittle desert and turquoise ocean is inhabited by amazing indigenous people – the Wayúu – who eat goats and lobsters, make beautiful hammocks but bad houses, have no proper roads and never enough water to drink.

Everything you read about La Guajira points to extreme heat, dehydration and absolutely no water anywhere (apart from that salty sea), so I have filled every spare inch in the car with water bottles. Except now it’s going to rain.

“Mummy just sent a text saying La Guajira is about to be hit by a cyclone,” says my daughter, “What’s a cyclone?” A storm, I reply. “Don’t worry, I packed an umbrella.” But I am worried. Having read some things about La Guajira over the years, it seems the last thing you want there is heavy rain.

I base this partly on one of my favourite books, Smokescreen, which relates how 1970s marijuana smugglers would y tonnes of Santa Marta weed from this lonely peninsula to Florida in clapped-out DC3s until it rained and the old planes skidded and crashed on clandestine dirt strips. The hippy narcos would burn the bales and get rescued by the Wayúu.

The book is a great yarn and paints a thrilling picture of this lawless corner, even if it is a bit out of date. The wild and empty Alto Guajira is still a smugglers paradise, but also firmly on the tourist trail, though most visitors take a guided jeep tour from the main city of Riohacha of which there is a wealth of info online.

Our plan is to drive our own car, but there is scant data on that, and getting lost, ambushed or bogged down all seem possible, now with the unexpected thrill of a cyclone. But at last we have left Bogotá behind. Our course is set. It’s La Guajira or bust.

A day later we have made it up the Ruta del Sol, and skirted the eastern flanks of the Sierra Nevada de Santa Marta. North of Valledupar the sky gets wider, the road emptier and the terrain flatter and drier, with goats and cardon cacti.

Cuatro Vías is a junction of straight roads which cut through La Guajira as they lead into a vast void that includes Venezuela to our East. A lunch of goat stew is interrupted by the rumble of a hundred-wagon coal train over the sooty viaduct above us, and here among the greasy pailas of fried entrails, there is the first sign of the region’s chronic water shortage. When I ask to wash my hands, the restaurant owner offers me a bowl of water that turns out to be the dish-washing bowl. As I plunge my hands in among greasy plates, I ponder how this exchange of bacteria will work, and in whose favour.

The Wayúu’s water crisis is as much about quality as quantity. Not only is there not enough water, but what water there is often gets polluted, causing diarrhoea and malnutrition. This, combined with poor hygiene, has triggered a health crisis which has killed thousands of Wayúu in recent years.

The Wayúu are Colombia’s most numerous indigenous population. More than 100,000 live in the Colombian La Guajira, and more across the border in Venezuela. Their desert lifestyle is finely tuned to annual rains that fill local earth dams, and snow-melt rivers from the nearby Sierra Nevada de Santa Marta that feed the desert water courses.

But the precious liquid is becoming scarce because upstream dams siphon it off for agribusinesses, and the huge coal mine at El Cerrejón in the south of the department squanders many mil- lions of gallons each day washing down hot coal ats. The hardships the Wayúu suffered when the Río Ranchería was diverted to benefit the world’s largest open-pit mine, has been documented by the courageous Colombian journalist Gonzalo Guillén in The River that was Stolen. Meanwhile, as water tables evaporate, remote communities must survive on water from stagnant ponds and salty wells.

So rain won’t be a bad thing, I think, even if it does mess up our holiday plans. But for now, the sun is still shining with no rain clouds in sight. Our next stop, the town of Uribia, is strung out over a parched plain, and hot, hot, hot.

On the road out of town, we stop to admire the collection of vintage and clapped-out jeeps which have also stopped to tank up: some are remarkable contraptions, rusted to the chassis and literally held together with string. For now, my 28-year-old Montero – by the far the oldest car in any Bogotá parqueadero – looks like the best ride and a crowd of Wayúu gather round to hitch a lift.

With sacks of food on the roof and the car lled with family, we head northeast onto the fast dirt road that runs to Puerto Bolívar, the mine’s rail terminus and seaport. Our Wayúu passengers are fascinated when I talk in English to the kids, and in turn teach them some Wayuunaiki until we drop them at the entrance of their ranchería. Here, the landscape dramatically changes to a crusty desert like those seen in Star Wars movies, with mineral-coloured hills and sparkling salt flats. So far, the sea is nowhere in sight.

We hit our first ambush at the turn-off to the beach, our destination for the night. I stop briefly to check the map and within seconds a host of wiry Wayúu kids launch themselves from a nearby culvert – the only shade around – and storm our car yelling “dulces, dulces.”

I throw a handful of sweets out the window, but this drives them into a frenzy as they fight over the meagre offerings, some climbing on the car now, their little hands reaching into the windows. My kids are aghast.

Before culture shock sets in, and their parents, who are running towards us waving hand-woven mochilas, reach us, I head west towards the sunset and Cabo de la Vela, following a vague braided dirt track that crosses salt pans and riverbeds, and follows dried-up creeks.

In every settlement, Wayuu children are lying in wait, with string across the road, ready to besiege tourists to a chant of Sweets, Sweets! I feel bad about ignoring them, but my reasoning is, if there is little water and sanitation, then I doubt the kids are brushing their teeth, so tossing hard candy from a window is hardly heroic.

My idea is confirmed by a large poster in the hostel where we park in Cabo de la Vela – “Don’t make our people beggars. Don’t throw them sweets and coins.” In smaller letters, words of wisdom: “If you want to help the communities buy our artesanía.” This makes sense, so we backtrack to a ranchería where there are stalls with beautiful crocheted bags swaying in the wind, and we are able to have a pleasant and relaxed interaction with the community.

A bit further up the coast, we find barren beaches and a windswept headland called Pilón de Azucar, with a shrine to the Virgin of Fátima, but known to the Wayúu as Jepira, the place where the spirits of the dead depart. We climb the conical hillock to look at the empty vastness of the peninsula, then beachcomb among fossilised corals. We drive back to Cabo to watch the kite-surfers skim across the shallow bay until sunset.

Later, at the restaurant, several guests talk about the impending rainstorm. Our Argentinian waiter dispenses with the niceties. He warns us that the creeks will ll up and the tracks turn to mud. “It will be hard to get out.” But the night is dry and skies clear. After the hostel generator switches off at midnight, my son wakes. Missing his nightlight he begins to fret. “Why is it dark? Is it the cyclone?”

I explain that not everywhere in the world has electrical power. I lead him by the hand to contemplate the desert sky, it is moonless but laden with stars. As a city boy, he gasps in wonder at his first sight of the Milky Way, our home galaxy, and celestial river of light.

Next morning, we face rivers of a more prosaic nature – gullies of rain-water that will fill the barren creeks we crossed to get here – as a grey line of rainclouds marches across the northeast horizon. The forecast was right. Rain has finally come to La Guajira, and there’s nothing wrong with that.