Ice Age Floods National Geologic Trail
Ice Age Floods National Geologic Trail
At 3.5 miles wide and 400 feet tall, Dry Falls was once the largest waterfall on Earth -- ten times the width of Niagara and nearly three times its height -- yet today not a single drop of water flows over its colossal basalt cliffs. During the Missoula Floods, an estimated 200...
Narrated audio coming soon · full transcript below
Stand at the Dry Falls overlook and you are standing at the lip of the largest waterfall the Earth has ever known. Not the largest that exists today. The largest that has ever existed.
When the ice dam holding back Glacial Lake Missoula failed, a wall of water roared across eastern Washington and slammed into this spot. The falls you would expect, the water, the mist, the roar, are gone. Everything else is still here: a cliff three and a half miles wide and over 400 feet tall, carved in a matter of days. Niagara Falls, for comparison, is about a mile wide and 165 feet tall. Set four Niagaras side by side, make them twice as tall, and shut the water off. That is what you are looking at.
The floods did not trickle over this cliff. They overtopped it, a torrent hundreds of feet deep, plucking blocks of basalt the size of houses and carrying them downstream. The quiet lakes at the base are plunge pools, where the falling water drilled straight into bedrock.
Why it matters: most landscapes are shaped over millions of years. This one was shaped in a single weekend, and then it happened again, dozens of times.
Bring this stop into the classroom: NPS “Investigating Ice Age Floods” Teacher’s Guide →
At 3.5 miles wide and 400 feet tall, Dry Falls was once the largest waterfall on Earth -- ten times the width of Niagara and nearly three times its height -- yet today not a single drop of water flows over its colossal basalt cliffs. During the Missoula Floods, an estimated 200 million cubic feet of water per second plunged over these scalloped precipices with four major cataracts, creating a curtain of whitewater that would have been visible for miles and audible for dozens more. The falls were carved as floodwaters poured down the Grand Coulee, each successive flood eroding the cliff face backward and deepening the plunge pools that are now serene lakes at the base of the cliffs. The Dry Falls Visitor Center perched at the rim provides a panoramic view that makes the scale suddenly real -- you can see where the falls once thundered and the lakes they carved below. Adventurous visitors can kayak on Dry Falls Lake or Deep Lake at the base of those 400-foot cliffs, paddling through a cathedral of basalt that once roared with the most powerful waterfall in geological history. This is the single most iconic site on the Ice Age Floods trail and the one place where the story tells itself at a glance.
Sun Lakes-Dry Falls State Park is a 4,027-acre park in Coulee City, Washington. It is open year-round; campground reservations available April 1 to October 31 (96 standard sites, 41 full-hookup sites). Discover Pass required. The Dry Falls Visitor Center is open seasonally (typically May through September) and overlooks the 400-foot, 3.5-mile-wide cliff. The visitor center has been undergoing planning for renovation.
Dry Falls is the single most dramatic erosional landform on the trail and one of the world's largest known former waterfalls — about 3.5 miles wide and 400 feet tall, roughly four times the width of Niagara. During peak Missoula-flood discharges down Upper Grand Coulee, water flowed over the entire cliff face at depths estimated at hundreds of feet, with discharges of approximately 65 cubic kilometers per hour. The cataract retreated upstream as a series of plunge-pool collapses, leaving the dry coulee and string of lakes visible today (Park Lake, Deep Lake, Lake Lenore, Soap Lake). Multiple flood events between roughly 18.2 ka and 14.0 ka contributed to the retreat. In 2023, the International Union of Geological Sciences (IUGS) designated Dry Falls as one of the First 100 IUGS Geological Heritage Sites, recognizing its global scientific significance.
The IUGS Geological Heritage designation in 2023 is the most prominent recent recognition. Cosmogenic dating (Balbas et al. 2017) places key flood pulses at 18.2 ka and refines the timing of Upper Grand Coulee opening to roughly 15.6 ka. Ongoing renovation planning for the visitor center is documented through Washington State Parks.
The Lower Grand Coulee Chapter treats Sun Lakes-Dry Falls as its flagship interpretive site, with frequent field trips and partnership programming with State Parks. IAFI maintains a dedicated page.
May–September for full visitor-center access and warm weather; winter visits are possible for the overlook but the campground and most facilities close. Allow at least half a day to combine the overlook, the Umatilla Rock trail, and a drive south through the coulee.
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.
Ice Age Floods National Geologic Trail
Most Pacific Northwesterners know how awesomely majestic and stunningly beautiful Dry Falls is, if only from the pictures that seem to show up everywhere. If you haven’t been there in person yet you definitely need to make that trek into central Washington. The drive through the lower Grand Coulee, as awesome as it is, is only the teaser for the view from the Dry Falls Visitor Center. But if you really want to get into the majesty, consider taking a kayak down to Dry Falls Lake or Deep Lake, at the base of those monstrous cataracts.
The dirt road to Dry Falls Lake isn’t for the faint of heart, and a good, high clearance SUV is recommended. But paddling the lake near the base of those 400 foot high cliffs is worth the effort. Bordered by reeds and accompanied by waterfowl, an hour-long paddle around the lake is leisurely, relaxing, and totally absorbing. And who knows, you might end up in someone else’s fantastic photo of Dry Falls from the Visitor Center.
The road to Deep Lake is paved, so it is a much easier place to get to. And the ramp at the lake makes getting in and out pretty easy… just be careful of the slippery algae on the ramp. Once you’re on the lake an hour’s paddle will take you from an area bordered by rolling hills to a section bounded by high vertical walls. Don’t fall out in this area because there’s nowhere to climb out or beach your boat to climb back in. Still, it’s astoundingly interesting to get up close and see the variety of textures in the basalt walls.
Of course, you can also do some great hiking in both areas, though climbing the blade takes quite a bit of effort and confidence, but the view is pretty spectacular. Unfortunately, the way back down isn’t any easier than the way up. Choose your route carefully.
Location: Grant County, Washington, United States 99371
MANAGED BY:Washington State ParksWebsite:https://iafi.org/go-do/washington/
Dry Falls is a 3.5-mile-long scalloped precipice with fou