The passing of the teenage girl was confirmed by the Helsinki police.
The accident took place before midnight when three teenage girls decided to descend down the plastic-coated landing slope while seated.
The girls crushed into a steel cable in the midst of the descent.
According to Inspector Jari Nikonen, the cable hit one of the girls on the neck and she died on the spot.
The other girls were injured and were rushed to hospital.
Nikonen said it was dark and the lights were off at the time of the accident.
Around 20 young people were present at the site which is popular with youths during nights out.
The news was first run by Finnish language tabloid Ilta-Sanomat.