The short answer: wind does not push roofs off — it lifts them, peeling from a free edge the way it lifts an airplane wing. The Interlock® system is documented under ICC-ES ESR-1790 with wind uplift resistance to 177.5 pounds per square foot, and its panels interlock on all four sides, so there is no free edge to start the peel. The written warranty covers winds to 120 mph installed to manufacturer specification.
Why the Gorge is a special case
The Columbia Gorge is the only near-sea-level passage through the Cascades, and it works like a wind tunnel between the wet west and the dry east. Hood River built an entire sport on that wind. What it means for a roof in Hood River, Mosier, Rowena or The Dalles is sustained loading, gust after gust, season after season — the exact duty cycle that works exposed fasteners loose and finds every lifted shingle edge.
How uplift failure actually happens
An asphalt shingle is held by adhesive strips and nails along one edge; wind pressure differential lifts the unbonded edge, and once one course peels, the failure cascades. Screw-down metal panels do better until their gaskets age. The engineering answer is to remove the free edge entirely: every Interlock panel locks to its neighbors on all four sides and fastens to the deck with concealed fasteners the wind never touches.
What the paperwork says
ICC-ES ESR-1790 is the code-compliance report that documents the system’s wind uplift resistance to 177.5 psf — an evaluation-service listing, not a marketing figure. On top of it sits the Guardian warranty’s written 120 mph wind coverage installed to manufacturer specification, in a region where our documented installs run from Hood River black slate to Deep Charcoal in The Dalles — 25 completed installations on record across the two towns since 1999, photographed in the gallery.
East-Gorge bonus: the sun
The Dalles adds high-desert UV and roughly 50 freeze-thaw cycles a year. The Alunar® 70% PVDF coating is warranted 30 years against exactly that, and CRRC-rated colors reflect summer heat.
Gorge homeowners can see county specifics on the Hood River and Wasco pages, or go straight to a written estimate.
