Withrow Moraine and Jameson Lake Drumlin Field erosion resulting from the Missoula Floods, which laid bare many layers of the basalt flows on the edges of the plateau at Grand Coulee and Moses Coulee. Two million years ago the Pleistocene epoch began and Ice age glaciers invaded the area. They scoured the Columbia River Plateau, reaching as far south as the middle of the Waterville Plateau highlands above the Grand Coulee and south to the head of Moses Coulee. In some areas north of the Grand Coulee they were as much as 3 km (10000 feet) thick. Grooves in the exposed granite bedrock are still visible in
Plum Coulee Plum Coulee Plum Coulee is an unincorporated urban community in the Municipality of Rhineland within the Canadian province of Manitoba that held town status prior to January 1, 2015. It is west of Altona, one hour southwest of Winnipeg and half an hour from the United States border. It is also the former home to the Plum Coulee Xpress hockey club. It has a man-made beach located in town. Philanthropist Saidye Bronfman was born in Plum Coulee. Plum Coulee's population of 800 is growing through land development. Working with local land owners, the former Town of Plum Coulee developed a