Unusual blue lightning observed in Tuusula, southern Finland during winter snowstorm

In the early evening on Wednesday, Iiris Tuominen from Tuusula was outside clearing snow when she noticed a bright flash illuminating the dark sky. “The light was incredibly bright and distinctly blue,” Tuominen recalled. Once inside, she set her phone to capture a video, hoping to document the unusual phenomenon. After waiting for about fifteen minutes, another flash occurred.

When the footage is played slowly, it shows a blue light flashing in the sky followed by the streetlight in the frame turning off. It’s likely that the lamp has a light-sensitive dusk sensor since it turned back on after the bright blue flash faded.

This day has seen multiple reports of lightning. A meteorologist from the Finnish Meteorological Institute, Petri Hoppula, shared that there have been observations of lightning activity in southern Finland. Earlier on Wednesday, lightning was seen in Espoo. According to lightning detection equipment, one ground strike and three intra-cloud flashes were reported, with the last intra-cloud flash noted at 5:30 PM, coinciding with Tuominen’s video capture in Tuusula.

Intra-cloud lightning occurs within clouds and does not hit the ground. Hoppula noted that the flashes were also observed near Forssa, approximately 100 kilometers from Tuusula. He mentioned it’s possible the intra-cloud flash could have been visible across a wide area during dusk. Additionally, there might have been lightning in the Tuusula region that the detection equipment failed to capture, especially as it may not pick up strikes in low-hanging clouds. Although rare in winter, lightning can still occur during this season, particularly during snowfalls due to the static electricity generated from snowflakes colliding with one another.