#6 of 10 slideshows from the region showing the impact of Glacial Lake Missoula and the Ice Age Floods #iceagefloods

A glacier is capable of carrying large rocks, often for quite a distance. When the glacier melts, those rocks get deposited in new location, not just physically but often geologically out of place. These are glacial erratics.

Ice floats, even chunks of glacier ice carrying large rocks. During the Ice Age floods, such ice rafts were pushed great distances by the massive floodwaters. Rocks from Canada and Montana have been found in central Washington and as far away as the Willamette Valley, south of Portland, Oregon.

Some ice rafts ran aground on the Waterville Plateau in Washington's Douglas County, creating a huge concentration of glacial erratics there.

The Photos (in order)

F15A0357 - This massive basalt glacial erratic is located along Highway 172 in Douglas County; that's my car to the left that it towers over; imagine the size of the ice raft and the amount of water needed to float this rock several miles

F15A0358 - Just up the road there is another huge glacial erratic, this one surrounded by a number of farm buildings

F15A0348 - Most of the glacial erratics deposited on the Waterville Plateau are much smaller; but they are big enough to create obstacles in farm fields

F15A0347 - More glacial erratics on the Waterville Plateau

F15A0168 - When Ice Age floodwaters channeled though Grand Coulee reached its southern end near present day Soap Lake, the water fanned out and slowed down, depositing the ice rafts and rocks across a broad plain along Highway 17

F15A0174 - A large erratic deposited south of Grand Coulee

I15A0399 - Erratics can be seen high above Crown Point Vista near Grand Coulee Dam; this gives you an idea of how deep the water was here during peak flooding

P13A0046 - Erratic Rock State Natural Site near McMinnville, Oregon features this erratic from the Ice Age floods, which at 36 tons is the largest known erratic from the floods in the Willamette Valley; it was carried here from Canada

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