Just south of Grand Teton National Park rumbles the magnificent Popo Agie (pronounced po-po-zsha) River. Right now it roars by, all the glacial meltwater causing it to spill over its banks. The Popo Agie plunges into the yawning dark mouth of a cave, only to reemerge half a mile away. I watched as the churning white water vanished into the cave, then hiked to the point where it rises back to the surface. There plumes of mud in the clear water betrayed the force with which the water bursts forth from inside the earth.
A very cool spot!