Snowmelt flows to a cold eave, refreezes and creates a reservoir that can move under roof coverings.
Failure path
- Step 1: Heat loss melts snow upslope.
- Step 2: Meltwater reaches a cold eave.
- Step 3: Ice accumulates and blocks drainage.
- Step 4: Water backs up under roofing laps.
- Step 5: Interior staining appears during freeze-thaw cycles.
What makes this pathway plausible
The timing, location and operating or weather trigger should repeat. A diagram shows a mechanism; evidence from the actual house determines whether it applies.
Best next observation
Record the trigger and compare the nearest materials, components and routes before opening finishes or choosing a repair.
Verification after repair
Recreate the original trigger when safe, then confirm the symptom does not return and affected materials are stable or drying.
Trigger→Pathway→Symptom→Verification
Simulation boundaryThis pathway explains a plausible mechanism. It does not establish that the mechanism is active in a specific house without matching evidence.
