Cache consists of a clear Rubbermaid container with logbook,
pencil, pencil sharpener, standard cover sheet, and flyers of the
Ice-Age Floods Institute (IAFI). The IAFI is a non-profit
organization devoted to informing and educating the public about
these unique geologic events that shaped the Pacific Northwest as
recently as 13,000 years ago. See www.iceagefloodsinstitute.org,
for more information.
Cache Elevation = 1330 ft
General Directions: From SR 28, drive 1 mile south on
Road U NW, and then 2 miles west on Road 9 NW. Park at a pull off
at the base of the long hill, where road flattens out onto Babcock
Bench.
West Bar Overlook
From the West Bar Overlook geocache is one of the best views
anywhere of giant current ripples left behind by cataclysmic
Ice-Age floods. The route to the geocache crosses over a rocky flat
called Babcock Bench. Babcock Bench is an elevated, flood-swept
rocky terrace that can be traced along the east side of the
Columbia River all the way to Vantage, 20 miles to the south. Most
of Babcock Bench is composed of the more flood-resistant top of the
Grand Ronde Basalt Formation. Floodwaters plucked away and
transported the overlying, more easily eroded Wanapum Basalt
Formation along the bench.
From the geocache, at the edge of Babcock Bench, is a wonderful
view looking down onto West Bar, which is blanketed with one of the
most classic examples of giant current ripples. (Take care
walking along the edge of the bench. In places its an almost
vertical, 750-ft drop to the river below.) The orientation of
the giant current ripples indicates they formed from an Ice-Age
flood restricted to the Columbia River Valley (i.e., from the
north) at the end of the last glacial cycle, probably between
12,000 and 13,000 years ago. The ripples average 24 feet in height
and are 360 feet apart and composed of boulders up to 4.5 feet in
diameter. The ripples currently lie a full 150 to 250 feet above
river level. Based on ripple size and spacing, geologists have
estimated the floodwaters were about 650 feet deep when the ripples
formed. That means the flood the created the West Bar megaripples
must have rose to at least the height of Babcock Bench, where the
geocache is located.
Other Ice-Age floods coming down the Channeled Scabland, filled
the Quincy Basin and spilled over Babcock and Evergreen Ridges from
the east before plunging into the Columbia River valley. These
floods carved
Potholes Coulee and
Frenchman Coulee, two of the most spectacular flood coulees
anywhere along the flood's route. The height of the largest
scabland flood must have been at least 1425 ft elevation, based on
a high spillover channel cut across Babcock Ridge that lies just
southeast of the cache site.
To experience more incredible features left behind by the
Ice-Age floods try finding these other geocaches placed by
geologist Bruce Bjornstad:
Staircase Rapids
Upper Goose Lake
Frenchman Coulee Rib
Rattlesnake Slope Erratics
Devils Canyon
Saddle Mountains Overlook (Earthcache)
Wallula Gap Overlook
Potholes Coulee
Lake Sacajawea Flood Bar
