Washington County, CO Roof Snow Load - 20 psf
What ASCE 7 says about snow load in Washington County
That's Washington County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. The physics-based figure alone would be 14 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 20 psf for flat and low-pitch roofs here, which is the number that actually governs.
Converted to something you can actually eyeball on a roof: about 44 in. of fresh powder, 16 in. once it settles and packs down, or just 4 in. if it's turned to ice. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Washington County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#1,223 of 2,758
- Colorado rank#15 of 24
- Population4,771
- Annual snowfall, NOAA normal32.2 in.
- FIPS08121
Where Washington County's figure sits nationally
Out of 2,758 rated US counties, Washington County sits at #1,223, the top 44% nationally - #15 of 24 within Colorado. That's 2.3 psf above Colorado's own county-average design load of 17.7 psf.
Near 39.9658°N 103.2097°W, FIPS 08121: Washington County counts 4,771 residents and a 20 psf map value, which the code's own factors turn into 20 psf.
How much it actually snows in Washington County
Most winters bring Washington County roughly 32.2 in. of snow - NOAA's normal at WOODROW 6NNE, CO US, 20.4 mi off. (fresh vs. packed vs. ice explains why.)
Read this before you rely on it
Washington County's number above is ASCE 7-22's default case, not a custom calculation: ordinary residential occupancy, heated, sited on ground that's neither fully sheltered nor fully exposed. Any one of those changing - pitch, exposure, heating, occupancy - moves the real figure.
Nothing here substitutes for an address-level number. Get one free, in about a minute, from the ASCE 7 Hazard Tool using your own coordinates rather than Washington County's county-wide figure. Details: the calculation guide.