Ice Age Floods National Geologic Trail
Ice Age Floods National Geologic Trail
The Wanapum Vista Pullout offers sweeping views of Frenchman Gap -- a water gap carved through the Saddle Mountains by the Columbia River and dramatically widened by the Missoula Floods. The gap is a dramatic notch cut through the basalt anticline of the Saddle Mountains, and...
The Wanapum Vista Pullout offers sweeping views of Frenchman Gap -- a water gap carved through the Saddle Mountains by the Columbia River and dramatically widened by the Missoula Floods. The gap is a dramatic notch cut through the basalt anticline of the Saddle Mountains, and during the floods it served as a critical passage for the enormous volume of water draining the Quincy Basin. Floodwaters poured through the gap with enough force to widen it significantly beyond what the Columbia River had carved over millions of years of normal flow. The gap's walls show flood scour marks and polished surfaces at elevations far above the modern river, evidence of the extraordinary depths the floodwaters reached. From the pullout, the view extends across the Columbia River to the gap itself, with the Saddle Mountains stretching in both directions and the Columbia flowing through the breach below. The contrast between the narrow gap and the wide basin on either side makes the hydraulic dynamics immediately comprehensible: this was a bottleneck that accelerated the floodwaters and concentrated their erosive power. Frenchman Gap is one of the most photogenic and geologically instructive stops along the Ice Age Floods trail.
The Wanapum Vista (also called the I-90 Scenic Viewpoint or Columbia River Scenic Overlook) is a roadside pullout on eastbound I-90 just west of Vantage, Washington. Free, open year-round, no facilities. Adjacent Frenchman Coulee (often labeled "Frenchman Gap" in older literature) is accessed via the Silica Road / Vantage Road exit (Exit 143); the coulee is part of the WDFW Columbia Basin Wildlife Area and a Discover Pass is required for vehicle access at the trailheads.
The Wanapum Vista looks east across the Columbia toward Sentinel Gap and the Columbia Plateau; on a clear day flood-scoured benches and Wanapum Basalt cliff faces are visible across the river. Frenchman Coulee, immediately east, is one of three "Quincy Cataracts" — Frenchman, Potholes, and Crater coulees — where Missoula floodwaters that filled the Quincy Basin via the Drumheller Channels spilled westward over Babcock and Evergreen ridges, dropping ~1,000 ft (from ~1,425 ft at the spillover lip to ~400 ft at the modern river) and ripping out the horseshoe-shaped recessional cataracts seen today. Columnar Frenchman Springs Member basalt was undercut and plucked block by block as the cataract retreated headward; the coulee floor sits well below the surrounding plateau. The vista pullout does not interpret the floods specifically — its interpretive panels emphasize the Ginkgo Petrified Forest and Wanapum Indigenous history — but the geology is on full display.
No site-specific dating updates published for the Quincy cataracts since the Balbas et al. (2017) regional 10Be chronology.
The IAFI Ellensburg/Wenatchee Valley Erratics chapters run periodic field trips through Frenchman Coulee. No permanent IAFI panel at the vista; interpretation is the responsibility of Washington State Parks / Ginkgo Petrified Forest.
Best photography light is morning (east-facing view from the vista). Combine with a hike down into Frenchman Coulee (the WTA "Frenchman Coulee" trail loop is 4–6 miles depending on route) for one of the most accessible flood-cataract experiences in Washington.
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.