This field trip guide covers the geology of some of the areas affected by two of the best documented catastrophic events in Earth's history: enormous basaltic lava flows that began to cover the land about 17 million years ago (Baksi, 1989) and giant glacier outburst floods (termed jc)kulhlaups) that started about 15,300 years ago (Waitt, 1985). These events are in large part responsible for the shape of the landscape of eastern Washington, where the Earth's youngest basalt plateau was swept by the largest documented floods in geologic history