A thunderstorm struck the city of Oulu on Tuesday evening, leading to flooded streets and traffic chaos.

An estimated 56 millimetres of rain water fell on the city during the first three hours of the storm, which began at about 6pm, with 11.3 millimetres falling in the first hour.

The massive influx of water led to roads being closed and a number of traffic accidents, including a multi-vehicle collision at the intersection of Haukiputaantie and Kiiminkijoentie/Martinniementie.

In addition, the Finnish Meteorological Institute (FMI) estimated that the region between Oulu and Siikajoki was hit by almost 5,000 lightning strikes by 10pm, noting that his was an "exceptionally high" figure.

Due to the heavy winds, the rescue services have been called upon to carry out several rescue and damage control operations.

According to the regional Kaleva newspaper, excessive rain water led to flash flooding in a number of neighbourhoods around the city.

The Finnish Meteorological Institute (FMI) on Wednesday said thunderstorms were approaching Finland from the west after days of unusually high temperatures.