Yosemite's Vernal Falls. (Jonah M. Kessel, Tahoe Daily Tribune / AP Photo)
Three hikers in Yosemite are presumed dead after going over Vernal Falls on Tuesday afternoon. Witnesses said the three climbed over a metal guardrail at the top of the 317-foot waterfall and did not heed warnings to get out of the rapidly moving water. The search was called off on Wednesday morning. There have been six water-related deaths in Yosemite this year, including the three hikers in this incident.