An Ice Age Relic

Palouse Falls in southeastern Washington is a lovely cascade 198 feet high. However, it appears rather insignificant in its huge basin, which is over twice as deep as the falls and far wider than the falls would be capable of eroding, even over millions of years. The secret is that the basin in the picture was carved 13 to 15 thousand years ago by our old buddies the Missoula Floods. The remnants of glacial Lake Missoula swept across this area again and again, every time an ice jam impounding the lake in northwestern Montana broke. An incredible volume of water roared through here, filling and even overflowing the basin, gouging out the basalt in a torrent of rapids of almost unimaginable power.

Just above and to the left of the falls are these towers of columnar basalt. They somehow survived the torrents, but all the rock around them was swept away. The towers seem vaguely Tolkienesque to me.

Palouse Canyon extends south from the falls. The little river in the big gorge wasn't always so insignificant. It completely filled the canyon...and then some...during the largest of the floods. The Palouse used to flow into the Columbia via the Washtucna Coulee to the northwest, but the floods overtopped that coulee and diverted the river southward, over the falls into the Snake.

The basalt cliffs in the canyon are majestic. They formed about 15 million years ago when vast quantities of lava flowed out of the ground again and again, covering much of Oregon and Washington thousands of feet deep. Each eruption produced a layer of basalt...you may be able to see some of the layers if you blow up this pic. The same type of cliffs can be seen in the Columbia Gorge, Grand Coulee, and near John Day Oregon. For that matter, they also make up Devils Postpile in the Cali Sierra.

A good shot of the falls and their basin...also a faint rainbow at the base of the cascade.