Why it matters

• Blaine's high water table does not directly cause roof level ice damming, but Blaine homeowners already understand water intrusion risk well given how common sump pumps are here, and an ice dam deserves the same attention.

• Poor attic insulation that lets heat escape and warms the roof deck from underneath.

• Inadequate attic ventilation that keeps the underside of the roof warmer than the outside air.

• Air leaks around recessed lights, attic hatches, vents, and chimneys that let warm household air reach the attic.

• Heavy snowfall followed by freeze thaw cycles which are common through a Minnesota winter.

• Roof design and older or worn roofing materials that let water back up under the shingles once ice has formed.

When it makes sense to act

• As soon as ice ridges appear, the same way a sump pump alarm would be treated. Blaine homeowners already used to monitoring for water intrusion at the foundation can apply that same vigilance to the roofline.

• Before a leak reaches insulation or drywall. Once water is behind the shingles, the risk is the same regardless of what is happening with the water table below the home.