On the far side of the Alvord Desert's vast alkali playa, wild horses have beaten a trail from a desert spring to Big Sand Gap, a sandy notch in a palisade of cliffs.  During the Ice Age, when this desert's basin filled with a 30-mile-long lake, the water finally spilled out here, launching a colossal flood that roared down the Snake and Columbia Rivers to the sea.

Today, a trip to Big San Gap is still an otherworldly experience -- driving across a dry lakebed and scrambling to one of the loneliest viewpoints in the country.  Although the hike is not difficult, it is only for adventurers with routefinding skills, two quarts of water, long pants, a hat, sunglasses, and sunscreen.   . . .

This chapter is an excerpt from 100 Hikes: Eastern Oregon