Six people were injured in the incident. Five of the casualties were taken to Harrogate District Hospital for treatment and the other person was taken to Leeds General Infirmary suffering from chest pains.
Witnesses described seeing the slide being blown in strong winds around 50metres, over the top of an AA van, before coming to rest.
It is not believed that anyone was critically injured in the incident.
Officers have seized the slide and investigations are continuing at the scene.
The Health and Safety Executive has been informed and are also attending the scene of the incident.