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Ecosystems + Geology Hike: Wallula Gap

Join naturalist Mike Denny at Wallula Gap, a national natural landmark near the Columbia River. During this guided hike, learn about the formation of the unique landscape that receives fewer than 10 inches of precipitation per year. Denny will highlight plants and species that thrive in this terrain, enduring high winds and arid conditions.

The water gap was cut through the Horse Heaven Hills anticline — a prominent geologic feature—by the ancestral Salmon/Clearwater River, which later captured the Columbia and Snake rivers. Roaring through the gap hundreds of times, the Missoula floods were as much as 900 feet deep and as fast as 60 miles an hour. Dunes formed as the prevailing southwesterly winds blew sand from the Umatilla Basin.

Recommended reading: Where the Great River Bends

Registration: This year, we are offering "Pay What You Can" ticket options to make our events accessible for everyone. Suggested price is $45.

Event fees and donations ensure that we can continue to offer excellent and accessible programming throughout the year. Please email Katy Rizzuti katy@bmlt.org for more information.


Suitability:  Ages 14 and older; participants under 18 must be accompanied by an adult. All participants must be vaccinated.

Difficulty: Moderate 2-3 mile hike. Strong winds are possible and sun exposure.

Things to bring: Sturdy hiking shoes, windbreaker jacket, hat with a brim and tie, sunglasses, sunscreen, lunch, 2 L water in a refillable bottle, camera, journal, and a sense of adventure


PHOTOGRAPH BY MIKE DENNY