From the Billings Gazette: Geologists witness Y’stone explosion

Yellowstone National Park geologist Hank Heasler was lecturing a group of colleagues in Biscuit Basin on the rarity of hydrothermal explosions last week when Boom! A hot pool behind him exploded, spewing mud, rocks and hot water 50 feet in the air. Geologists know of only a handful of such unpredictable explosions in Yellowstone’s recorded history.