Adams County, WA Roof Snow Load - 20 psf
How much snow is too much for a roof in Adams County, WA?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Adams County to carry. 14 psf is what the ground-load formula alone gives; Adams County's 20 psf low-slope minimum (§7.3.4) beats it, so that figure is the one that governs on flat and low-pitch roofs.
Picture it, not just weigh it: 44 in. if it's fresh powder, 16 in. once it settles, or a mere 4 in. if it's ice. Modern-code homes carry a load like this without issue; an older addition, a carport, or any flat-roofed section is where it is worth checking first.
Adams County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#948 of 2,758
- Washington rank#2 of 10
- Population21,039
- Annual snowfall, NOAA normal14.6 in.
- FIPS53001
How Adams County compares
20 psf ranks #948 of 2,758 US counties with a mapped snow load (top 34%) - and #2 of 10 in Washington. That's 4 psf above Washington's own county-average design load of 16 psf.
Population 21,039 (FIPS 53001), roughly 47.0112°N 118.5129°W. The 20 psf ground snow load ASCE 7-22 maps here becomes 20 psf once the code's own design factors are applied.
Typical snowfall in Adams County, WA
NOAA's 30-year normal for Adams County: 14.6 in. of snow a year, from the LIND 3 NE, WA US station. (fresh vs. packed vs. ice explains why.)
What this Adams County figure assumes
This is a county-level reference figure for a typical heated home built to Risk Category II (ordinary residential), on a partially exposed lot - the assumptions ASCE 7-22 itself treats as the default case. A steeper roof, a fully exposed hilltop lot, an unheated structure, or a higher risk category all change the actual number.
Adams County's permit office wants an address-specific figure, not this county average - the ASCE 7 Hazard Tool is free, takes under a minute, and outputs a PDF most reviewers accept. Details: the calculation guide.