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:
Staircase Rapids
Upper Goose Lake
Frenchman Coulee Rib
Rattlesnake Slope Erratics
Devils Canyon
Saddle Mountains Overlook (Earthcache)
Wallula Gap Overlook
Potholes Coulee
West Bar Overlook