TWIN FALLS - BASE Jumping is a sport that, despite the simple act of jumping off of really high things, involves precision, quick thinking, and a lot of courage. Here's what it takes to become a BASE jumper at the Perrine Bridge. BASE jumper Sean Chuma packs his chute Friday evening, July 13, 2018, near the Visitor Center in Twin Falls. BASE, which stands for buildings, antennas, spans, and earth, are the objects of desire for which BASE jumpers fight against gravity for the briefest moment.