The Cheney–Palouse Tract of Washington's Channeled Scablands

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The Cheney–Palouse Tract of Washington’s Channeled Scablands SPRAGUE 231 e k LINCOLN SPOKANE C r a b C r e COUNTY SPRAGUE COUNTY

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RITZVILLE o u t h F o e S r k k WHITMAN C ADAMS r a a COUNTY b k L COUNTY C r e e e u water g 261 flow r a direction S p 26

127 r Map Area u PINE o During the last ice age, a lobe of the Cordilleran Ice Sheet formed an This map shows the CITY ice dam that blocked a major valley in what is now western topographic evidence of c LAMONT Montana, creating Glacial Lake Missoula. Between 15,000 and the Missoula Floods on a s 13,000 years ago the ice began to recede and the lake portion of the Channeled

S periodically breached the ice dam. These breaches Scablands in eastern Washington L created an estimated 40 catastrophic floods that known as the Cheney–Palouse L e I flowed westward during this time period. k scabland tract. Smooth, linear H k These ice-age floods, also known as the a features are former channels of the L L c Missoula Floods, swept across what is floods, while the more textured land U k K now eastern Washington and c adjacent to the pathways was higher in A o o R R onward to the Pacific Ocean elevation, and was thus unaffected by the A r

K along the Columbia River flooding. d corridor. The floods scoured e the landscape on a massive Flooded areas were often scoured down to b scale, leaving behind bedrock, as can be seen east of Sprague Lake scarred terrain known and the Karakul Hills. In the Cheney-Palouse as the Channeled scablands region, the former channels are also RITZVILLE Scablands. Flood EWAN occupied by dozens of lakes. The largest and features are so deepest scabland lake is Rock Lake in the huge, they can northeast portion of the map. be seen from space. In the area adjacent to the flooded ST. JOHN channels, much of the landscape is covered in loess (windblown glacial silt). Loess k e e covers the agriculturally productive Palouse region, C r k the area of rolling hills in the southeastern corner of o c R the map.

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