Wenatchee, Washington is often called the “Apple Capital of the World” or the “Buckle of the Power Belt of the Pacific Northwest”. Today the Wenatchee vicinity is known for the fruit industry, wineries, power generation, tourism and outdoor recreation. When you visit and look around the Wenatchee Valley, even today, much of the landscape was formed by Ice Age Flooding. Visit the Wenatchee Valley area to explore some of the interesting Ice Age Flood features found there.
Toward the end of the Pleistocene Ice Ages (17,000-12,000 years ago) much of the landscape in the Wenatchee area was changed substantially by catastrophic ice-age flooding. These flood(s), almost 1,000 feet deep, initiated out of glacial Lake Missoula in Montana, and some of the largest came through the Wenatchee area along the Columbia River drainage.
Prior to the Okanogan Ice Lobe blocking the Columbia River valley north of Wenatchee, the early Missoula flood(s) could follow the present day path of the Columbia River around the “Big Bend” area of north-central Washington into the Wenatchee area and further south. Take a drive north of Wenatchee on highways US 97 or US 97A to see evidence of this flooding.
As the Okanogan Ice Lobe advanced south it eventually blocked the Columbia River drainage north of Wenatchee. The water backed up by that Okanogan Lobe ice dam formed glacial Lake Columbia and forced subsequent ice-age floods to be funneled southward along the east edge of the ice lobe into Moses and Grand Coulees, and farther east through the Channeled Scablands of eastern Washington. When the Okanagan ice eventually retreated, one last flood from glacial Lake Columbia again followed the Columbia drainage through Wenatchee.
Massive boulders (some 40 feet in diameter) and erratics (rocks foreign to the area) were transported at the base of the flood waters and embedded in huge icebergs floating on the floodwaters. They were deposited along the hillsides throughout the Wenatchee area as the floods waned and the icebergs became stuck and melted. Those erratics prompted our Ice Age Floods Institute chapter name “The Wenatchee Valley Erratics”.
The two main erratic rock types in this area, granite and gneiss, are much different from the Eocene Chumstick Sandstone bedrock. The gneiss erratics transported a relatively short distance from outcrops just north of Wenatchee are often 10 feet in diameter. The nearest granite outcrops occur some 15 miles upstream in the Entiat area, so the granite erratics tend to be smaller, less than 3 feet in diameter. Some of the best locations to see these erratics are just south of the Old Wenatchee Bridge (first bridge over the Columbia River finished in 1908) along the Apple Capital Loop Trail near Patriot Plumbing & Heating, the Department of Social & Health Services and near the old train at Mission Street Park in south Wenatchee.
An enormous crescent-pendant Pangborn Bar topped with huge current ripples was deposited in east Wenatchee where the Columbia River drainage takes a right (easterly) turn. The bar elevation is 500 feet above the Columbia River today. On the surface of Pangborn Bar are giant current ripples with crests up to twenty feet tall and ripples spaced some 300 feet apart. Travel up Grant Road, 4th Street in East Wenatchee and then out onto Batterman Road northwest of Rock Island to travel across the entire Pangborn Bar from west to east. The giant current ripples are best observed on 2nd or 4th Streets, where these roads go up and over the current ripples east of Nile Avenue in East Wenatchee, Washington.
Just about a mile northeast of Pangborn Memorial Airport is a very significant archaeological site, the East Wenatchee Clovis Site (Richey Clovis Cache), discovered in 1987 and excavated until the site was closed and covered in 2004. This site lies on top of one of these current ripples. Pristine Clovis spear points as well as other archaeological specimens (about 11,000 years old) were discovered and some are now on display at the Wenatchee Valley Museum and Cultural Center in Wenatchee.
Article from Brent Cunderla, April 2024