The Colville National Forest disproves the widely held notion that Washington state lies flat east of the Cascade Mountains. Today's 1.1 million acre forest was first shaped over 10,000 years ago by Ice Age glaciers that carved three major valleys of today's Columbia, San Poil-Curlew, and Pend Oreille River flowing north into Canada before entering the Columbia River. These million acres in the northeast corner roll like the high seas. Three waves of mountains run from north to south, separated by troughs of valleys. These ranges -- the Okanogan, Kettle River, and Selkirk -- are considered foothills of the Rocky Mountains. Read full article.