Three people were in the car that drove into the water, and one person was in the car that drove into a mountain wall and was trapped.
One person was trapped and was taken to hospital by ambulance helicopter. He was unconscious when he was taken away, says Morten Gunneng, duty officer at police.
The other three people were taken to hospital by ambulance.
"We are investigating the incident as negligence in traffic and causing bodily harm. There is also a suspicion of drunk driving against the person who was most seriously injured," says Morten Gunneng.
Initially, there were alarms that people had been hit, but the emergency services were later able to determine that everyone involved was travelling in the cars.
