FEMA Roof Snowdrift Design Guide

This FEMA document, from August 2019, provides a design guide for three-dimensional roof snowdrifts. It includes procedures and design examples consistent with the intersecting drift provisions expected in the 2022 edition of the American Society of Civil Engineers (ASCE) standard ASCE 7, detailing historical context, changes introduced in ASCE 7-16, and proposed criteria for ASCE 7-22. The guide covers examples of drift loads, snow densities, drift heights, and drift surcharges based on different wind directions and roof geometries.