High Quality Content by WIKIPEDIA articles! Vortex is a stand-up roller coaster at California's Great America. It is a slightly shorter version of the one at Carowinds. It was Bolliger & Mabillard's second coaster after Iron Wolf at Six Flags Great America and officially opened on March 9, 1991. The ride has a reputation for the uncomfortable head-banging some experience while riding.A stand-up roller coaster is a roller coaster designed to have the passengers stand through the course of the ride. These roller coasters are very intense, and generally carry taller height restrictions than other rides.