DENVER (KDVR) — On Tuesday, visitors at Yellowstone National Park fled when a hydrothermal explosion occurred a few miles north of the famous Old Faithful geyser. No one was injured, but the event destroyed a nearby boardwalk and prompted officials to close the Biscuit Basin area of the park for the rest of the year. As alarming as the video and subsequent damage seemed, the phenomenon is a normal, common occurrence at Yellowstone, happening at least once each year. Officials with the U.S. Geological Survey told Nexstar hydrothermal explosions like the one that occurred this week are “not a sign...