Snow Drift On Gable Roofs

Leeward snow drifts occur when wind blows snow off of a higher elevation roof down onto an adjacent lower roof.

Snow drift on gable roofs.

The gable roof exhibited a slightly higher accumulation coefficient than the flat roof. Snow can either blown from the low side of the roof towards the high side or is blown off the higher area of the roof onto the lower projected side. Windward snow drifts occur when wind blows snow from a lower elevation roof towards the wall of an adjacent higher roof. Ground snow drift is a 2 hfor more complex geometries a reasonable approach is to match the cross sectional area of the odd shaped drift to that for a roof step with the same fetch and ground load 50 faq 4 odd drift geometries approach used for gable roof drifts in 7 05 area for roof step d for a triangular gable drift with a.

The amount of additional snow load or surcharge depends on the difference in height of the two adjacent roofs and the lengths of roof perpendicular to the drop in height. Current provisions of snow load in load standards codes are primarily based on limited case histories and engineering judgment. An analysis of snowdrift patterns and accumulation coefficients which are representative of the depth of snow cover for flat and gable roofs showed that accumulation coefficient decreases in accordance with increases in wind speed. Gable roof is a typical roof style which is commonly used in many countries.

For the case of a roof step where leeward and windward. Resulting drift formation was envisioned as perpendicular to the roof step para pet wall or ridgeline. For gable roofs a rectangular drift surcharge was prescribed and the rectangular shape remained unchanged everywhere along the ridge line.