The Hessdalen Lights

Mystery rating

In the Hessdalen valley in central Norway, strange lights appear in the sky. They can be white, yellow or red, and they sometimes hover for over an hour. Scientists have been measuring them since 1983 with an automatic station. Nobody has fully explained them.

Why it's famous

Hessdalen earned its reputation through sustained scientific attention rather than a single dramatic event. Sightings began in late 1981 and peaked between 1982 and 1984, when hundreds of residents, including farmers, teachers, and police officers, independently reported white or yellow spheres hovering low over the valley, some moving against the wind. In 1983, Norwegian scientists launched Project Hessdalen, spending the winter of 1984 recording data with cameras, radar, magnetometers, and seismographs. They logged 188 observations and matched some visual sightings to radar returns, but reached no explanation. Since 1998, Østfold University College has run an automatic measurement station that monitors the valley continuously, later joined by Italy's CNR institute and its EMBLA research campaigns. Sightings still occur, roughly ten to twenty times a year, mostly in winter. The leading hypothesis involves an ionized plasma generated by the valley's unusual metal-rich geology, though this doesn't fully explain reports of structured shapes or sharp directional changes.

History

Hessdalen is a valley about 12 kilometers (7.5 miles) long, dotted with farms, located south of Trondheim and close to the old copper-mining town of Røros. The strange events began in late 1981 and reached their peak between 1982 and 1984. During this time, hundreds of people reported seeing the lights independently – farmers, teachers, police officers, and drivers passing through. Often, these sightings were up close and at a low altitude. In 1983, a group of Norwegian scientists launched 'Project Hessdalen.' They spent the winter of 1984 in the valley, equipped with cameras, devices to analyze light (spectrum analyzers), radar, magnetometers (to measure magnetic fields), and seismographs (to detect ground tremors). They recorded 188 observations, took photographs, and even picked up radar signals that matched what people were seeing with their eyes. But despite all this data, they couldn't explain the lights. In 1998, Østfold University College set up the Hessdalen Automatic Measurement Station, which has been constantly monitoring the sky ever since. Italy's CNR institute later joined in with its EMBLA campaigns. Today, there's a student field station and a small research center in the valley, and Norwegian universities use it for instrumentation courses. Sightings still happen, though not as frequently – usually about ten to twenty times a year, mostly in winter. Four decades of collecting data have helped scientists narrow down the possibilities, but they still haven't solved the mystery. This long-standing enigma is quite unusual in this field, which is exactly why physicists keep coming back.

The full story

You'll find Hessdalen about a two-hour drive southeast of Trondheim. Honestly, the journey there, winding through the Gauldalen valley and up onto the plateau, is an adventure in itself. Don't expect big tourist attractions like ticket booths or cafes here – that's part of its charm. Instead, you'll discover a peaceful, working valley with a small information center and observation spot right in Hessdalen. There's also a clearly marked 'Blue Path' walking route with great viewpoints, and, of course, the vast, open sky. Try to visit in winter. This is when most sightings happen, usually between November and February. The nights are incredibly long, stretching for sixteen hours, and the air on the cold, clear plateau is perfect for stargazing. Drive your car to one of the marked viewpoints high above the valley floor and settle in for a long watch. You'll need patience, a thermos of something hot, and seriously warm clothes – think sleeping-bag-level warmth. Bring a camera on a tripod with a fast lens and set it to take pictures automatically over time. The best records of the phenomenon have come from people who set up their camera to keep snapping while they watched. Even if the lights don't appear, you'll be treated to one of the darkest skies in Europe, and there's a very good chance you'll see the spectacular Northern Lights (aurora) at this latitude. Make the charming town of Røros your base. It's only half an hour south and is a UNESCO World Heritage site, famous for its old mining history. Imagine tar-coated timber houses and grass-covered roofs, all looking magical under a blanket of snow. You'll find great places to eat and sleep here. While you're there, ask the locals about the lights. Most have a story or two and will tell them with a shrug that somehow feels more believable than any official report. Round out your trip by trying dog sledding, exploring the Røros copper mines at Olavsgruva, and perhaps stopping at Trondheim's magnificent Nidaros Cathedral on your way back. Summer visits are lovely for hiking, but the nights never get truly dark, and without that darkness, there's nothing to see.

Legends & sightings

The leading scientific idea tries to explain the lights using geology and chemistry. The valley floor contains a lot of metal, and its rock structure is unusually broken up, with deposits of scandium, copper, and zinc. A river carrying sulfurous (sulfur-rich) water also flows through the area. One theory suggests this creates a kind of natural battery effect across the valley, producing an ionized gas – a plasma – that would glow, drift, react to wind and magnetic fields, and show up on radar. Another idea points to burning clouds of dust from old mine waste. A third theory considers electric charges caused by stress in the rocks. Italian researchers have measured radio and light emissions that match what you'd expect from plasma, and the plasma model is currently the most respected scientific explanation. However, none of these theories fully account for reports of clearly structured shapes, sharp right-angle turns, objects that seem to keep pace with cars on the road, or the sheer length of some sightings – some lights have been watched for over an hour. Local people are surprisingly calm about it all. Farmers talk about "lysene" (the lights) in the same casual way they might discuss the weather. Older folklore from the Trøndelag region also mentioned them, calling them "hulderlys" – the lights of the hidden folk. These were lights seen over bogs and mining areas, meant to be observed but never followed. After forty years of study, the most compelling truth is this: something real is happening in that valley, and no one can yet say exactly what it is.

Can you visit?

Yes. Hessdalen is an open valley with public roads and marked places where sky watchers gather, including a small observation post. There is no ticket, no gate and no guarantee of seeing anything. Most reported activity happens in the dark months.

How to get there

1. Fly into Trondheim (TRD) or take the train to Røros. 2. From Røros, drive north towards Ålen and into the Hessdalen valley. 3. A car is essentially required. Roads are quiet and buses are rare. Allow a couple of hours of driving from Trondheim, more in winter conditions.

Before you go

Go between late autumn and early spring for long dark nights, but expect winter driving conditions. Bring serious warm clothing. You will be standing still outdoors in the cold. Use winter tyres and check road reports if driving in the snow season. Bring a torch, hot drinks and full fuel. Book accommodation in Ålen or Røros. Options in the valley itself are very limited.

What to expect

A wide, quiet Norwegian valley with farms, forest and very little light. In the daytime there is nothing to see beyond the landscape and the small information point. At night you park, wait and watch. Many visitors see nothing. Those who do usually describe slow moving lights low over the ridges.

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