YELLOWSTONE NATIONAL PARK, Wyo — YELLOWSTONE NATIONAL PARK, Wyo. -- Steam wafted over Hank Heasler as he stood on a boardwalk and watched water from Steamboat Geyser shoot into the air with an attention-grabbing "WHOOSH!"
"This could be it," the park geologist said excitedly, squinting against the morning sun at the impressive spray. But Heasler had no better idea than the tourists around him when the world's tallest geyser would next erupt.
Unlike Old Faithful, Steamboat is anything but predictable. It has gone as few as four days and as many as 50 years between major eruptions -- noisy, powerful spectacles that can send hot water 300 feet or higher and churn out dense steam for hours.
Recently, though, it has been more active -- its two eruptions so far this year came just weeks apart -- and the emergence of a forceful new thermal feature nearby has scientists like Heasler wondering: What's happening in Norris Geyser Basin, where Steamboat is located?
"That's the million-dollar question. It's changing more than anyone has noticed before," Heasler said. "Are we noticing because we're looking? Or because something is abnormal?"
Researchers are trying to find answers. They've installed monitoring devices throughout the basin -- near features such as Steamboat and in creek channels that collect water runoff from geysers -- to gather data on such things as water temperature and flow levels, basic information, they say, was previously lacking and could help unlock the mysteries of Norris.
Among them: What's bubbling beneath the shallow surface of the volatile basin and why has the basin floor been steadily bulging over the last few years?
Adding to the intrigue is Norris' location. The basin -- filled with hot springs, geysers and steam vents called fumaroles -- is outside Yellowstone's caldera, formed by the last volcanic eruption about 640,000 years ago and considered the hotbed for geothermal activity in the park.
Some 10,000 hot springs and geysers pock the park's landscape, their telltale steam often visible to tourists traveling park roads. But the Norris basin is frequently passed by, viewed from the car by motorists headed south to Old Faithful.
Perhaps the reason Norris is so dynamic, researchers say, is that there's molten material beneath the basin. Or, maybe, hot water from the caldera has pushed north to Norris.
