Attic ventilation under heavy snow.

Recent snowstorm shows the value of gable end attic vents.
Living in the heart of the Ohio snowbelt, large and heavy snowfall is common during the winter months. Roofs leaking due to ice backup problems are also common.
A house that has only ridge or other static venting on the roof will have ice backup problems as the warm air in the attic will not be vented to the outside. The warm attic air will warm the underside of the roofing and melt the snow. The snowmelt then runs down the roof to the cold eave and gutter and freezes into ice dams. Water above the ice dam then backs up under the roofing and leaks into the house.