The Helsinki Rescue Department received numerous alerts on flooding and damage in different areas of the city on Sunday morning.
In Vallila, water flooded streets and ground collapsed due to a burst pipe between Satamaradankatu and Aleksis Kiven katu, near Dallapénpuisto.
At around 7:30am, the rescue department was alerted of the situation at the intersection of Fleminginkatu and Aleksis Kiven katu. According to Toni Tannikoski, the department's on-duty fire chief, the water spread to properties and other streets nearby.
The area's water supply was then cut off. However, Tannikoski said that the road between Aleksis Kiven katu and Satamaradankatu was closed to traffic due to ongoing pumping operations to alleviate the flooding.
The cause of the pipe burst is not yet clear.
Other pipe bursts also occurred in Helsinki on Sunday morning. The rescue department also received calls regarding Violankatu in Hermanni and the area around Hietalahdentori and Bulevardi in Hietalahti. Traffic was disrupted in these areas as well.
Helsinki Police do not believe that the incident was a result of vandalism or sabotage.
"There are currently no indications of any such thing. The Rescue Department has already said publicly that it is due to a pipe burst," said Tuukka Skottman, inspector in charge at the Helsinki Police Department.
According to Skottman, the police have no current investigation, but were directing traffic.
HSY suspects old pipes
The Helsinki Region Environmental Services Authority (HSY) suspected that this could be a chain reaction of old pipes.
"There is no malice, no sabotage, it is possibly a case of this being a sequential chain reaction. Several pipe failures in the inner city area, which is due to the fact that we have a reasonably old pipe network," said Tommi Rantala, department director at HSY.
According to Rantala, disruptions in one of the main lines could have had caused pressure shocks throughout the connected network.
HSY said more problems may appear throughout Sunday afternoon and evening.
There were four confirmed leaks and one suspected lead. HSY is investigating the effects of the damage on the city's water supply. If there are significant disruptions, HSY is prepared to distribute water via mobile supply units.
"We can handle temporary distribution either using a mobile water container for distribution or otherwise, if pressurised water is unavailable. Mobile distribution points will be announced as necessary later on Sunday," Rantala told Yle.
The root cause of the problem will not be known for a few days, when HSY repairs and inspects the damaged sections of the network.
According to HSY, sediment can be released from the walls of water pipes due to changes in water flow direction and pressure fluctuations throughout the city centre. If the water is brown or cloudy, all taps should be run until it is clear.
HSY urges anyone with unclear water after 10 minutes to contact the water supply emergency hotline at (+358) 09 1561 3000.
Information added from HSY 12:20.
HSY sediment information and contact line added at 15:52.
Corrections 17:53: Comment from the on-duty fire chief initially said the cases were unrelated, but HSY suspects a chain reaction from main. The original story also incorrectly stated that the leak at the between Satamaradankatu and Aleksis Kiven katu was in Vallila not Kallio.