Green Monarch Ridge by Lake Pend Oreille ID
Green Monarch Ridge by Lake Pend Oreille ID NPS Photo

Ice Age Floods National Geologic Trail

Federal Recreation Area · Washington · National Park Service

At the end of the last Ice Age, 18,000 to 15,000 years ago, an ice dam in northern Idaho created Glacial Lake Missoula stretching 3,000 square miles around Missoula, Montana. The dam burst and released flood waters across Washington, down the Columbia River into Oregon before reaching the Pacific Ocean. The Ice Age Floods forever changed the lives and landscape of the Pacific Northwest.

Plan your visit

Know before you go

Phone
(509) 237-9722
Official site
www.nps.gov
Managed by
National Park Service

Getting there

Directions on Google Maps →

Things to do

Highlights: Tragic Events · Floods · Geology

Activities & features: Guided Tours · Self-Guided Tours - Walking · Self-Guided Tours - Auto · Junior Ranger Program

Photos

  • Large butte with lake in the foreground
    NPS
  • Steamboat rock in the foreground with Banks Lake in the distance
    NPS
  • Dry Lake lake bed and falls blanked with snow.
    NPS Photo
  • A overhead shot of the Dry Falls area
    NPS/Cline

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140 parks mapped in Washington

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Guides for the trip

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Sources: National Park Service · updated 2026-08-12