BILLINGS - Numerous community entities were mobilized over the weekend, after a pile up of about 30 cars left dozens of people stranded on the Yellowstone River Bridge Saturday. Montana Highway Patrol (MHP) Captain Keith Edgell says a 'perfect storm' of dangerous driving conditions, including ice and limited visibility due to snow, contributed to the multiple vehicle crash on I-90 leaving two hospitalized. Around seven troopers were working the scene Saturday, with two primary troopers leading the crash investigation, while a Sergeant and Captain Edgell assist with gathering information. The two major hospitals in Billings, Billings Clinic and St. Vincent Healthcare, train for multi-casualty emergencies, so they are at the top of their game when disasters like this strike.