Douglas County, WA Roof Snow Load - Case Study Area
Why doesn't Douglas County have a snow load number?
ASCE 7's own snow load map has no single figure for Douglas County: the terrain is complex enough that the code (§7.2) requires an elevation-specific study rather than a county-wide value. That is the map being accurate, not a data gap.
FIPS 53017, population 45,795. 386 US counties get this same case-study treatment; Douglas County is one of them.
Douglas County at a glance
- Population45,795
- Annual snowfall, NOAA normal20.5 in.
- FIPS53017
Douglas County's snowfall, most winters
20.5 in. a year: that's Douglas County's NOAA 1991-2020 snowfall normal, measured at CHELAN, WA US (15.6 mi away). See the density guide.
Before you rely on Douglas County's number
Treat the Douglas County figure as a starting point, not a final answer: it assumes standard occupancy, a heated structure and a moderately sheltered site, per ASCE 7-22's own defaults. Exposed terrain, an unheated building or a steeper roof all shift the real number.
For a real application, skip the county number and go straight to the ASCE 7 Hazard Tool - enter your coordinates and it returns a site-specific figure a plan reviewer will recognize. (How this figure is calculated.)