Steamboat Geyser hasn't erupted three times in a year since 2003, but Reuters reports that it hit that mark on Friday—which might prompt concern that something bigger is about to happen at Yellowstone National Park, which sits on top of a 44-mile-wide active volcano. Geologists aren't sure exactly what is going on at the park's lesser-known geyser, but USGS Yellowstone Volcano Observatory chief Michael Poland says, "there is nothing to indicate that any sort of volcanic eruption is imminent."
The earlier eruptions occurred on March 15 and April 19, after a silence of more than three years. What would be more worrisome: If the park's hydrothermal systems dried up, an indicator that magma could be creeping upward. "Yellowstone hasn’t had a volcanic eruption for 70,000 years! Geysers erupt all the time," says another USGS geologist. The Washington Post, meanwhile, is worried, calling the volcano "a disaster waiting to happen." (Read more Yellowstone National Park stories.)