Ice Age Floods National Geologic Trail
Ice Age Floods National Geologic Trail
Hole in the Ground Canyon between Bonnie Lake and Rock Lake is a textbook example of a cataract canyon -- a dry waterfall amphitheater carved by the Missoula Floods as they roared through the Cheney-Palouse scabland tract. The canyon's sheer basalt walls and horseshoe-shaped...
Hole in the Ground Canyon between Bonnie Lake and Rock Lake is a textbook example of a cataract canyon -- a dry waterfall amphitheater carved by the Missoula Floods as they roared through the Cheney-Palouse scabland tract. The canyon's sheer basalt walls and horseshoe-shaped headwall reveal where a temporary waterfall, possibly hundreds of feet tall, eroded backward through the basalt during successive flood events. The floods carved this canyon in a matter of hours during each event, ripping through layer after layer of Columbia River basalt and exposing the distinctive columnar jointing that now makes the canyon walls look like a giant's pipe organ. At the base of the canyon, enormous basalt blocks testify to the hydraulic forces that plucked them from the cliff face and tumbled them downstream. Rock Lake itself, an unusually deep and narrow lake filling a flood-scoured trench nearby, adds to the dramatic scabland scenery. The canyon is relatively remote and sees few visitors, making it one of the most pristine and undisturbed examples of flood-carved terrain in the scablands. This is the scablands at their most raw and unmediated.
Public viewing point on undeveloped land south of Cheney, Washington. No formal trail, no facilities, no fees. Access is via dirt/gravel roads and informal pullouts off Mullinix Road. Best treated as a windshield/short-walk stop; the canyon floor is private in places.
Hole in the Ground Coulee is part of the Cheney-Palouse scabland tract, one of the major south-trending channels carved by Missoula floodwaters spilling across the Columbia Plateau toward the Snake River. The site is named for a roughly 100-foot-deep plunge pool on the coulee floor — the toe of a recessional dry cataract where floodwaters undercut a basalt ledge and quarried out a pothole. The cataract retreated upstream during repeated flood events between 18.2 and 14 ka (Balbas et al. 2017). The coulee shows the classic anastomosing pattern Bretz described in 1923: braided channels around streamlined loess "islands," dry cataracts, and basalt scabland with no soil cover.
No site-specific peer-reviewed work since Balbas et al. 2017. The Cheney-Palouse tract was included in the broader Waitt and O'Connor (2021) USGS megaflood review.
The Cheney-Spokane Chapter (based at Eastern Washington University) leads field trips through Hole in the Ground and the broader Cheney-Palouse tract; it is the IAFI chapter most directly responsible for the site. Eastern Washington University geology faculty publish field guides covering it.
Best April through June when wildflowers are out and creek pools are still ponded. Mid-summer is dry and hot. Wear sturdy boots; the basalt is sharp and the access is unmaintained.
Every site along the trail will receive the full Terrain360 capture treatment: ground-level 360° panoramas, drone aerial imagery, and photogrammetry-based 3D models that visitors can spin in their browser. This page reserves the slots; the imagery flows in as field capture completes.
Ground-level 360° panorama, every step along the feature, captured by Terrain360 field crews.
Drone flyovers reveal the geometry of catastrophe — ripple marks, gravel bars, and scour patterns invisible from the ground.
Photogrammetry and Gaussian-splat models let visitors rotate, measure, and inspect features in detail-page WebGL viewers.