Grand Coulee, formerly a wide, dry valley, is a geologic anomaly left over from the last Ice Age. At that time, a glacier repeatedly dammed an upstream tributary of the Columbia River and formed a huge lake in what is today Montana. When this prehistoric lake repeatedly burst through its ice dam, massive floods poured down from the Rocky Mountains. So great was the volume of water that the Columbia River overflowed its normal channel and, as these floodwaters flowed southward, they carved deep valleys into the basalt landscape of central Washington. As the floodwaters reached the Cascade Range, they were forced together into one great torrent that was so powerful, it scoured out the Columbia Gorge far downstream, carving cliffs and leaving us with today's beautiful waterfalls. With the end of the Ice Age, however, the Columbia returned to its original channel and the temporary flood channels were left high and dry. Early French explorers called these dry channels coulées, and the largest of them all was Grand Coulee, which is 50 miles long, between 2 miles and 5 miles wide, and 1,000 feet deep.
Read More
Ask a Question
Do you have a travel question about this destination or can you provide a tip to a fellow traveler?
Join the discussion with Away.com's in-house experts in our travel Q&A.
Hotels
We're sorry, we have no hotels matching this destination.
Powered by Trip.com