Pine needles, fine debris and forest
Properties along Gatineau Park and the wooded roads get a particular mix: maple leaves in the fall, but mostly pine and spruce needles that drop more or less year-round. Needles don't form a layer you can see from the ground, they pack into a dense mass at the bottom of the gutter and wedge into the downspout openings.
That's why a Chelsea gutter can look clear from below and be fully blocked at the outlet. Flushing the downspouts is the step that matters most here.
