Ice Age Floods National Geologic Trail
Ice Age Floods National Geologic Trail
The Chinook Scenic Byway winds through the Mt. Baker-Snoqualmie National Forest and Mount Rainier National Park, offering views of Cascade Range volcanic peaks and alpine landscapes that provide dramatic context for the Ice Age Floods story. While the Cascades themselves were...
The Chinook Scenic Byway winds through the Mt. Baker-Snoqualmie National Forest and Mount Rainier National Park, offering views of Cascade Range volcanic peaks and alpine landscapes that provide dramatic context for the Ice Age Floods story. While the Cascades themselves were not carved by the Missoula Floods, they played a crucial role: the mountain range acted as the western wall that channeled floodwaters southward through the Columbia Gorge rather than allowing them to spread westward. The byway passes through terrain shaped by alpine glaciation -- a different but related chapter of the same ice age that produced the Missoula Floods to the east. Mount Rainier's massive glaciers today are remnants of the same Pleistocene ice age that spawned the Cordilleran Ice Sheet whose lobes dammed the Clark Fork and Columbia Rivers. The scenic drive connects the volcanic and glacial stories of the Pacific Northwest, showing how the same climatic forces that built ice dams in Montana also sculpted the Cascade peaks. This is the western bookend of the ice age story, where fire and ice shaped a landscape visible from every switchback.
The Chinook Scenic Byway is the 85-mile SR-410 corridor between Enumclaw and Naches, Washington, climbing over 5,430-foot Chinook Pass through Mount Rainier National Park and the Mt. Baker-Snoqualmie National Forest. Chinook and Cayuse passes are closed each winter due to avalanche danger; the 2026 reopening is scheduled for Friday, May 22, with seasonal closure typically resuming in late November. The byway is free to drive; standard National Park entrance fees apply for excursions into Mount Rainier National Park.
This is a tangential Ice Age Floods site. The byway is primarily a Cascades volcanic / alpine landscape — Mount Rainier glaciers, andesitic lavas, subalpine meadows — and the floods themselves did not run through the Cascade crest. The "flood" connection on the eastern descent is indirect: the route drops into the basalt flows of the Columbia Plateau at its western edge, where the same Columbia River Basalt Group lavas that the Missoula floods later scoured downstream are exposed in canyon walls. IAFI's page on the byway notes the High Cascades and Columbia Plateau basalt flows but does not identify on-route flood deposits or erosion features. If the public-facing detail page covers this site, lead with: this is a scenic-context stop for understanding the volcanic stage on which the floods later played out, not a stop with on-trail flood evidence.
No flood-specific research at this location. The byway is not a target of Missoula-flood field studies.
IAFI maintains a Chinook Scenic Byway page and a downloadable 25-page itinerary guide, but the content focuses on scenic and basalt context rather than specific flood features.
Drive between late May and late October. Allow a full day with stops at Tipsoo Lake, Sunrise (Mount Rainier), and the eastern descent toward Naches. Best for fall color in late September.
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.