The roof snow loads specified in ASCE 7-22 are based on or related to the ground snow load. This approach is used because of the relative abundance of ground snow measurement information in comparison to roof snow load measurements. For most of the central Midwest, bounded by Indiana on the east and Nebraska on the west, the ground snow loads are primarily a function of latitude. The equal ground snow load lines generally run East to West. In the eastern United States, ground snow load generally increases with latitude, but two additional variables also influence ground snow load: site elevation and the distance from the shoreline. The new ground snow load maps and Hazard Tool have eliminated the need for the seven state tables in ASCE 7-16. To avoid requiring structural engineers to perform snow load calculations where snow does not control the design, ASCE 7-22 has added low ground snow load clarifications and exceptions.
Abigail J. McCauleyKevin KnuutiPaul F. Mlakar
Thomas W. SchmidlinDennis J. EdgellMolly A. Delaney