Lacamas Lake near Camas, Washington, was bored into the landscape by kolks -- spinning underwater vortices generated when the Missoula Floods funneled through the eastern end of the Portland Basin. These liquid tornadoes drilled into...
Lacamas Lake near Camas, Washington, was bored into the landscape by kolks -- spinning underwater vortices generated when the Missoula Floods funneled through the eastern end of the Portland Basin. These liquid tornadoes drilled into bedrock with devastating force, excavating the depression that now holds the lake and its surrounding wetlands. The floods reached this area after squeezing through the Columbia Gorge, and as they spread into the wider Portland Basin, complex eddies and vortices formed wherever the flow encountered obstacles or changes in terrain. Lacamas Lake is the result of one such vortex system, which scoured a deep basin in rock and sediment. Today the lake is a popular recreation area surrounded by a scenic park with trails, waterfalls on Lacamas Creek, and lush second-growth forest. The basalt outcrops around the lake show polished and scoured surfaces characteristic of extreme flood erosion. Standing on the lakeshore, it takes imagination to picture this peaceful scene as the inside of a swirling maelstrom -- but that is precisely what it was, 15,000 years ago.
Open year-round, free public access. Lacamas Lake Regional Park (Clark County) is on the south shore in Camas, Washington, with trailheads, parking, restrooms. Lacamas Heritage Trail (3.5 miles one-way) runs along the lake.
Lacamas Lake fills a depression scoured by Missoula floodwaters that overtopped the Columbia River valley near Camas and cut a secondary channel north across what is now the Camas–Washougal lowland. The Portland Basin received the full force of Missoula floods slowed and backed up by the Kalama narrows downstream, slack-water silts and ice-rafted erratics are found at elevations as high as 400 feet here, even though the lake surface sits only ~180 feet above the modern Columbia. The lake basin itself is the eroded floor of a flood-cut channel, now dammed by a small early-20th-century paper-mill diversion. This is a peripheral, slack-water flood feature rather than a primary high-energy site.
No site-specific updates found since the USGS Geologic Map of the Camas Quadrangle (Evarts, 2004, SIM 3017) mapped the surficial flood deposits. The broader Portland Basin flood stratigraphy was updated by Beget and Eichelberger (2018) studies of slack-water rhythmites in the Sandy River area.
The Lower Columbia Chapter covers Camas/Washougal sites and includes Lacamas Lake on its field-trip rotation. The City of Camas highlights the lake's flood origin in trailhead signage but there is no dedicated IAFI interpretive panel.
Spring (March–May) is best for the camas blooms the city was named for and the lake's full pool. The Heritage Trail's north-end Round Lake section best shows the flood-channel geometry.
Three vantages no single photograph can hold, the same treatment that made Dry Falls legible.
Ground-level panoramas along the feature, so the scale of the flood landscape is something you stand inside.
An aerial reveals the geometry of catastrophe: scour, channels, and bars that are invisible at eye level.
A model of a key outcrop you can rotate and measure in the browser, the rock itself, on the page.
Capture window mid-June through mid-July 2026 · slots fill on this page as the campaign delivers.
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 Cinematic timeline · 3D flood · every captured site