slgwv's photos with the keyword: Spokane Floods

An enormous dry waterfall in the middle of the Grand Coulee, eastern Washington state, USA. It was formed by the gigantic Spokane (a.k.a. Scabland, Missoula) floods during the last ice age, when a glacial dam in what's now northernmost Idaho would collapse periodically. The glacier, a tongue of the Cordilleran Ice Sheet, backed up glacial Lake Missoula into the Rocky Mountain trench, and so all that water would suddenly go sloshing across eastern Washington. The floods left behind the Channeled Scabland, a distinctive topography of buttes, coulees (flat-bottomed canyons), channels, closed basins, and enormous ripple deposits.

Columnar jointing at the base of a Columbia River Basalt flow exhumed by the Scabland floods.

South of the main part of Frenchman Coulee, across the column wall.

Looking out the coulee to the southwest on a bleak winter day. Note my vehicle (outlined); in those days you could drive on the jeep roads in the coulee!

In the outwash debris below Sentinel Gap, somewhere in the Priest Rapids wildlife area. This boulder has lain there for >10^4 years now, and is somewhat worse for wear! Beer can for scale. Note how some of the original surface is preserved at the lower right.

With the raising of the water table by the Columbia Basin Project in the mid-20th century, lots of quasi-perennial streams now flow across the basin, and this one finds its way into the coulee.