Washington Ground Snow Load by County and City

Washington sets no ground snow load at state level, so every figure comes from a county or city building department. Twelve figures from Washington counties and cities are set out below, each with the ordinance or code amendment it was printed in. 19 states work this way, which is why a search for one Washington figure comes back with several different answers from several different pages, all of them correct for the place they were written for. twelve Washington figures, running from 15 (Revised Ground Snow Load, psf) at Bellingham to 588 (Revised Ground Snow Load, psf) at Mt. Baker Ski Area, every one of them quoted from the document it was printed in. Nationally 235 figures were read across 33 states.

The county or city building department (for example Whatcom County Planning and Development Services, Chelan County Community Development, King County Department of Local Services): the county looks the value up against the parcel. In its own words: “For accurate snow load information for your site call the Whatcom County Planning and Development Services Office at 360-778-5900 with your parcel number and have a Plans Examiner look it up for you.”

Part of Washington is a case study area, meaning the published document expressly declines to give those places a figure and sends the designer back to the local building department for one. 16 states carry a rule like this, and it is the commonest reason a search for a single number comes back empty. The rule reads: “All areas within the county that exceed 950 feet in elevation shall use the Chelan County GIS Map to establish appropriate ground snow loads.”

The figure moves with elevation in Washington, which is the hardest case for a reader: two houses a mile apart and a thousand feet apart take different numbers, and 13 states are keyed this way. The published Washington figures run from 15 (Revised Ground Snow Load, psf) to 588 (Revised Ground Snow Load, psf).

Washington State Building Code Council, Washington Administrative Code chapter 51-50 adopts International Building Code (2021 edition). Washington adopted it as written. The adopting rule reads: “The 2021 edition of the International Building Code , including Appendix E, published by the International Code Council is hereby adopted by reference with the exceptions noted in this chapter of the Washington Administrative Code.”

A ground snow load is a weight per unit area and not a depth, and the two are joined only by the density of the snow on the day, which is why the published documents give the load and leave the depth out. Wet spring snow and dry January snow of the same depth are different weights on the same roof. The county or city building department (for example Whatcom County Planning and Development Services, Chelan County Community Development, King County Department of Local Services) works in loads for that reason, and so does every figure set out below.

A Washington figure for an address the documents below do not cover comes from the county or city building department (for example Whatcom County Planning and Development Services, Chelan County Community Development, King County Department of Local Services). The document behind it is the adopting rule, published by each county or city building department, read on September 23, 2026. It establishes the point this way: “Snow loads for Whatcom County are determined by the study produced by the Structural Engineers Association of Washington (SEAW) as revised in January of 1997.”

14 of 50: Connecticut, Indiana, Maryland, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New Jersey, North Carolina, Rhode Island, Utah, Vermont, Wisconsin. The other 36 split into 17 that adopt the national code without a snow amendment and 19 that leave every figure to a county or city building department. That is the single most useful fact about this subject and no one state's own website carries it.