Surprise blast of rock, water and steam sends dozens running for safety in Yellowstone

A surprise eruption of steam, water and dark-colored rock and dirt that shot dozens of feet into the sky sent people running for safety in Yellowstone National Park. The hydrothermal explosion happened Tuesday morning in Biscuit Basin, a group of hot springs a couple miles north of Old Faithful Geyser. Video posted online shows a couple dozen people watching from a boardwalk as the eruption sprayed and grew in front of them. They ran to get clear as water and debris began to fall. The eruption damaged the boardwalk but no injuries are reported. The basin is closed for visitor safety.