Wallula Gap

backed up

Lake Lewis was formed when the restricted flow of waters from periodic cataclysmic floods from Glacial Lake Missoula, pluvial Lake Bonneville, and perhaps from subglacial outbursts, backed up through the constriction formed by the Wallula Gap in the Horse Heaven Hills (southern Washington).

basalts flows

The basalts flows which are visible in the Wallula Gap were laid down during the Miocene Epoch, about 17 million years ago.

lewis and clark expedition

The Lewis and Clark Expedition (a.k.a. Corps of Discovery) first saw the Wallula Gap on October 18, 1805, as they headed downstream from their camp at the confluence of the Columbia and Snake rivers.

OpenStreetMap

https://www.openstreetmap.org/way/893222027

parking

https://www.openstreetmap.org/way/693934124 (Wallula Scablands Trailhead)
https://www.openstreetmap.org/way/1054873275 (Twin Sisters)
https://www.openstreetmap.org/way/484307790 (Climber’s trails)

random

Bureau of Land Management (Wikipedia) The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering U.S. federal lands. Headquartered in Washington, D.C., the BLM oversees more than 247.3 million acres (1,001,000 km2) of land, or one-eighth of the United States’s total landmass.[

tags

valley

valley in

valley of

Columbia River

widening

The Wallula Gap was widened about the 14th millennium BC, by the historic flow of the Salmon, Snake, and Columbia rivers combined with the glacial waters that poured across the Channeled Scablands during the Missoula floods.

Wikidata

https://www.wikidata.org/wiki/Q3565546

Wikimedia

https://commons.wikimedia.org/wiki/Category:Wallula_Gap

Wikipedia

Wallula Gap (Wikipedia) Wallula Gap (/wəˈluːlə/) is a large water gap of the Columbia River in the Northwestern United States, in Southeastern Washington. It cuts through the Horse Heaven Hills basalt anticlines in the Columbia River Basin, just south of the confluence of the Walla Walla and Columbia rivers.