Earlier this week, heavy rains and melting snow near Yellowstone National Park combined, causing rivers to overflow, flooding farms and ranches, washing out roads and bridges, and forcing the park to close. The Yellowstone River hit its highest level in decades, and the surge is now moving through nearby Billings, Montana. When Yellowstone National Park reopens—possibly as soon as next week—it will likely open only the southern half. Park officials are still assessing the amount of work needed to safely reopen the northern half.