Paasselka lights: why balls of light flash over the Finnish lake

On dark, moonless nights, glowing orbs appear over Lake Paasselkä. Residents of eastern Finland call them Paasselän pirut, or the Paasselkä lights. The lake occupies an ancient impact crater (as of 09/2026, article about Paasselkä). Similar lights occur in different countries around the world, but Paasselkä has its own history and its own name. Below we look at what is known about the phenomenon, where the crater came from, and how to reach the shore.

Paasselkä lights: what witnesses see

💡 In short:

• The Paasselkä lights appear as orbs of light above the water, forest, and nearby marshes.
• The phenomenon has been known since the 18th century, and local residents gave it the name Paasselän pirut.

© Regina-celina · CC BY-SAPhoto: Regina-celina, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

Witnesses describe the light as an orb or ellipse that hangs low above the water. It can move at varying speeds or stay in place, and sometimes several orbs are visible at once (according to the description of the Paasselkä lights). The color of the glow varies. Most often, witnesses mention a yellowish or greenish tint.

Some accounts attribute independent behavior to the orb. It supposedly follows a fisherman's boat or retreats from a flashlight beam, and its speed at times seems incredible. Such details are hard to verify, but they recur in descriptions from different decades.

The phenomenon has been known for a long time: the first records of it were made as early as the 18th century, and over time the lights entered local folklore under the name "devils" (according to the encyclopedia of local legends). They became widely known through the book by Sulo Strömberg about the villages of Kerimäki and Savonranta, published in 2006.

The glowing orbs have been filmed on camera more than once, and the footage confirms that this is a real observed light, not just old legends. The lights have been seen both over open water and over marshes in the lake's vicinity. If you come here looking for them, keep your camera ready, because the phenomenon lasts only a few minutes.

A lake in a crater: the geologists' version

Lake Paasselkä has an oval shape and lies in Southern Savonia. It is part of the Orivesi lake system, which belongs to Greater Saimaa. The body of water stretches almost 13 km in length and up to 9 km in width, its maximum depth reaches 75 m, and its surface lies at an elevation of 60 m above sea level (as of 09/2026, geological reference on the crater). There are no islands here at all.

The lake occupies a crater left by a meteorite impact. The impact origin was confirmed only after deep drilling, and since then Paasselkä has been called the ninth known impact crater in Finland.

Before the drilling, the oval shape of the body of water and magnetic anomalies pointed to an impact origin. The magnetic anomaly is concentrated in the center of the lake, and it is with this anomaly that some researchers link the appearance of the glowing orbs (according to the review of the Paasselkä lights).

Most Finnish craters are hidden under a layer of sedimentary rock, but Paasselkä lies exposed. That is why the lake and its shores are accessible for observation, and people come here not only for the lights but also for the geology.

Legends and scary stories

Local residents of past centuries considered the glowing orbs to be evil beings, which is why the word "devils" became fixed in the name. At the same time, people knew that light sometimes appeared over the water and nearby marshes.

The old legends have a practical meaning: in the dark near water, it is easy to lose your bearings. Quagmires, bogs, and darkness are dangerous on their own, without any mysticism. If you find yourself near a marsh at night, stay on the path and do not leave it for the sake of beautiful lights. Your safety matters more than spectacular footage.

Scientific explanations for the lights

Most often, will-o'-the-wisps over marshes are explained by gases from decaying plants at the bottom of the bog. In the dark, such gases produce a faint glow. This explanation fits the marshy shores well, of which there are many around Paasselkä.

There is also an optical explanation: some researchers attribute the lights to the refraction of light in layers of air above the water, that is, something like a mirage. In old descriptions of the lake, this interpretation appears especially often.

A separate line of inquiry is connected with the crater's magnetic anomaly. It is being studied, but a direct link between the anomaly and the orbs of light has not yet been proven. If you expect a precise answer from science, there is none yet. That is why the lake continues to attract observers.

Where the lake is and when to look

Paasselkä is located in eastern Finland, in the Savonranta area, which belongs to Savonlinna. The coordinates of the body of water are 62°09′ north latitude and 29°25′ east longitude (according to the encyclopedia overview of the lake). Savonlinna serves as a reference point for the trip, and from there the route goes through forests to the village of Savonranta.

There are no tickets sold for the lake, and there are no ticket offices or fenced viewing areas on the shore. The best time for observation begins in late summer, when the nights become truly dark. A full moon gets in the way: in its light, the faint glow is harder to make out.

Bring a headlamp, warm clothing, and plenty of time. If you are going for one night, it is better to keep a second day in reserve and not pin your plans on a single chance. During the day, there is also plenty to do at the lake: walks through the forest and views of the water.

⁉️🤔 Frequently asked questions

Why is Lake Paasselkä considered a crater?

The lake occupies a crater from a meteorite impact. Its impact origin was confirmed by deep drilling in 1999 (according to the reference on the crater).

What are the Paasselkä lights?

Paasselän pirut appear as orbs of light above the lake and nearby marshes. They move at varying speeds or stay in place, and sometimes several appear at once. Local residents gave them the name "devils" many centuries ago, and under that name they entered folklore collections.

Are the lights dangerous to people?

There is no direct evidence of harm: the glowing orbs have not attacked people. The danger comes from the place itself: the bog, the darkness, and an unfamiliar shore. So at night you should stay on the path and not walk toward the light across a bog, even if it seems close.

Can you see the lights on purpose?

There are no guarantees: the phenomenon is rare and irregular. It is easier to observe on dark nights in late summer and autumn, away from city lights. Sometimes the orb can be captured on camera, but more often it is seen only with the naked eye. Be patient, because waiting can take hours.

How do you get to the lake?

The lake lies in Southern Savonia, in the Savonranta area, which belongs to Savonlinna. Access to the shore is free. Plan the trip by car and allow extra time.

In short: what is worth booking

The Paasselkä lights cannot be sold or booked: you can see them only in the dark and with a bit of luck. If you have one night, pick a shore away from the village and wait. If you have time, come in late summer or autumn and combine observation with walks through the forests of Savonranta. If you are traveling with children, keep the route short and do not leave the path.

If you want to add more to your trip, start with our selection What to see in Finland.