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: 500 ft
General Directions: From the Pasco-Kahlotus Hwy. turn right (south) onto Snake River Road. After 5 miles park where road ends at the Snake River.
Lake Sacajawea Flood Bar
Lake Sacajawea Bar is one of the largest depositional features left behind by the great Ice-Age floods. Geocache is located along the Columbia Plateau Trail, a rails to trails project under development, with an excellent view of the bar.
The bar is located 15 miles upstream of Ice Harbor Dam, which created Lake Sacajawea, a man-made reservoir along the Snake River. The bar rises abruptly to 400 feet above the river, making it one of the tallest Ice-Age flood bars.
Lake Sacajawea Bar is a longitudinal bar divided into two segments. A taller bar lies just downstream of a basalt spur and is classified as a longitudinal-pendant bar. The largest floods, which came off the Channeled Scabland from the northeast, formed this pendant bar. Downstream, the bar narrows and hugs the northwest side of the valley to form a longitudinal-eddy bar. Its upper surface lies 140 feet lower than the pendant bar.
Lake Sacajawea Bar has undergone considerable environmental degradation from railroad construction and gravel mining since the early part of the 20th century. Much of the face of the bar, which is composed of loose gravelly material, sloughed off when the bar was undermined during construction of the railroad tracks at its base. Fortunately for geologists, these activities created several good exposures of the interior of the bar from which we can interpret some of the history and dynamics of Ice-Age flooding.
Many Ice-Age flood bars have succumbed to mining for the valuable gravel and sand they contain called aggregate. Lake Sacajawea Bar may face a similar threat. Washington State Parks, who own most of the bar, is considering destroying the entire bar by selling off the aggregate. Both the U.S. and Washington State Boards on Geographic Names, however, recently approved the formal name “Lake Sacajawea Bar” for this flood feature. Formal recognition of this significant natural resource, perhaps will bring more awareness to the bar and its impending destruction.
To experience more incredible features left behind by the Ice-Age floods try finding these other geocaches placed by geologist Bruce Bjornstad:
Upper Goose Lake
Frenchman Coulee Rib
Rattlesnake Slope Erratics
Saddle Mountains Overlook (Earthcache)
Wallula Gap Overlook
West Bar Overlook