A heavy rain and thunderstorm hit Central Finland on Wednesday night, causing local flooding and street damage.
Pyry Poutanen, a meteorologist from the Finnish Meteorological Institute, said the thunderstorm was accompanied by a warm, humid mass of air not typical for this time of year.
The overnight storm caused local flooding and water damage in Jyväskylä in particular, according to the city.
The city saw 20-30mm of rain in a single day, and an accumulation of 25.3mm was recorded at Jyväskylä Airport.
"That's about half a month's average rainfall. It came quickly and in a short time. The biggest problem with these types of heavy rains is that storm water networks can't keep up when water comes [at that pace]. There were floods in many urban areas," Poutanen said.
She said the storm offered relatively little wind, at about 10 m/s, sparing trees and power lines.
"Damage begins to happen when gusts of wind are at about 15 to 20 m/s," she said adding that the region managed to avoid major damage from the storm.
There were also a large number of lightning strikes during Wednesday night's storm, more than 7,000, most of which were within a 50km radius around Jyväskylä.
Poutanen said that the total average number of lightning strikes during the entire month of May across Finland is around 8,000.
Jyväskylä hit hardest
The worst of the damage in Jyväskylä was seen in the Kuokkala neighbourhood and northern areas of the city.
Parts of some streets were also left covered in sand and crushed stone and sand-paved sidewalks and sandy street curbs were partly washed away by the heavy rain.
The city said maintenance work is underway to repair the damage as soon as possible, noting that the Kammintie street would be closed off during the work.
Some of the road repairs will continue into next week, according to the city.
Small, sandy roads in the Viitasaari area were particularly hard-hit by Wednesday night's deluge.
National transport management firm Fintraffic reported on Thursday morning that there were several points along route 775 in Viitasaari covered in water, with flooding reported at least between Aholanmäki and Naarajärvi in Kinnula.
Fintraffic also said that drivers in the Tampere area reported flooded areas on the road from Saarijärvi's Honkatie road and Lonnikontie road in Viitasaari.