Tumalt Creek

[aircooled]

It could be buried. According the Friends of the Gorge, "Multnomah County designated the area that had been slated for
the subdivision as a “geohazard” zone, due to its potential for landslides. The designation proved prophetic in February 1996, when heavy rains and significant warming caused massive mudslides in the area. A nearby house was swept away in the slide, finally coming to rest just a few hundred yards from Interstate 84, where its broken frame still lies atilt today."

Yes, there were once plans to build a subdivision of "country homes" here.

[miah66]

I wonder if logging above this valley has had any impact on the instability of the area in the last 100 years?

[chameleon]

I guarantee it's had an impact. Starting around 1840, the Gorge was heavily logged for a century. Prior, there were always seasonal slides, but logging definitely exacerbated things. The pre-logging Gorge was biologically mature. The forest was largely fireproof, as the centuries had produced a lot of large, well spaced trees and densely rooted slopes. Once those were logged, the area became a tender box. Brush and densely spaced saplings grew from the dead roots of giants, and this is a recipe for vicious, fast fires. And logging camps were notoriously sloppy with fire. During the century after logging here began,
Gorge slopes were routinely ravaged by extreme fires, most often ignited by loggers.

Early photos show grossly denuded slopes throughout the Gorge. And once a slope has burned, it is much more prone to slides. Despite what many believe, logging, even as it's done today, has a lot of consequences, with more intense fires and more frequent landslides being two.

Who knows if the Tumalt slides would have been avoided... Probably not, given the magnitude. However, the alluvial fan and wreckage of the slide would have been lessened, and the potential buried falls might still be around.