Photograph everything before Thursday, including close-ups of the stained sheathing and wide shots showing the tarp, and date-stamp them. That matters because adjusters cover storm damage but typically not pre-existing rot, and you want a clear record of both. Your instinct is probably right that the wind found an already weak area. Don’t remove anything further until the adjuster has seen it. For the repair itself, GotRot covers this at igotrot.com/seattle-wa-siding-repair/ – they’re licensed, bonded and insured, and they can supply a written scope that separates storm damage from underlying condition, which helps your claim.
