During the Ice Age Floods, Badger Mountain near Richland, Washington, was an island poking above the swirling surface of Glacial Lake Lewis, its summit the only dry ground for miles in any direction. When the Wallula Gap bottleneck backed...
During the Ice Age Floods, Badger Mountain near Richland, Washington, was an island poking above the swirling surface of Glacial Lake Lewis, its summit the only dry ground for miles in any direction. When the Wallula Gap bottleneck backed floodwaters across the Pasco Basin, water rose to a maximum elevation of 1,250 feet above sea level, submerging the surrounding lowlands but leaving Badger Mountain's summit exposed. The mountain's flanks bear high-water marks and flood-deposited sediments at the 1,250-foot elevation, a visible bathtub ring from the temporary lake. Below this line, the mountain's slopes were scoured and reshaped by the standing floodwaters; above it, the original pre-flood terrain survives. Today Badger Mountain is a popular hiking destination in the Tri-Cities area, with trails offering panoramic views of the Pasco Basin -- the same basin that was repeatedly filled by floodwaters. From the summit, you can see the convergence of the Columbia and Snake Rivers, Wallula Gap in the distance, and the vast flat terrain of flood deposits stretching in every direction. It is the perfect place to grasp the scale of Glacial Lake Lewis.
Badger Mountain Centennial Preserve is a Benton County park in Richland, Washington, managed in partnership with Friends of Badger Mountain and the City of Richland. There are no entrance fees and trails are open year-round, dawn to dusk. The two main trailheads are Trailhead Park (525 Queensgate Dr) and Westgate Trailhead (5305 East PR 210). About eight miles of trail traverse the preserve.
Badger Mountain is one of the "Lake Lewis Isles", basalt ridges whose crests stood above the maximum stage of temporary Lake Lewis, the slackwater lake that backed up behind the hydraulic constriction at Wallula Gap during each Missoula flood. Lake Lewis reached roughly 1,200–1,250 feet above modern sea level; Badger's summit, at over 1,500 feet, remained an island during peak flood stages. From the ridge, hikers look out over the Pasco Basin floor where flood sediments and rhythmic backflood deposits accumulated, and across to Candy Mountain, Goose Hill, and Red Mountain, the other Lake Lewis Isles. Flood waters also helped plug the original Yakima River channel through Badger Coulee (Waitt 1980), forcing the ancestral Yakima to its current northward route.
No updates found since the long-cited Waitt (1980) Badger Coulee study and the Balbas et al. (2017) chronology, which puts the largest flood at ~18.2 ± 1.5 ka. The 2020 O'Connor et al. USGS review consolidates Lake Lewis backflood modeling.
Strong. The IAFI Lake Lewis Chapter (Tri-Cities) treats Badger Mountain as a flagship interpretive site and has installed at least four trailside interpretive signs along the preserve trails explaining the floods, Lake Lewis high-water marks, and the basalt geology. Friends of Badger Mountain maintains a dedicated "Ice Age Floods" page on its website.
Best in spring (wildflowers) and fall; summer can hit 100°F+ with little shade. The Canyon Trail (1.3 mi, hikers only) and Skyline Trail (2.9 mi, multi-use) both reach the summit and the interpretive signs.
Flood-extent overlay shows the maximum reach of the Missoula Floods.
The site in its place along the flood path, with the maximum flood extent drawn over the modern map.
View on the interactive map Searchable sites · 360° trails · flood reconstruction