Arapahoe County, CO Roof Snow Load - 20 psf
Arapahoe County, CO: your roof's ASCE 7 snow number, in plain English
Arapahoe County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. 14 psf is what the ground-load formula alone gives; Arapahoe 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.
In depth, not weight: that's roughly 44 inches of fresh, light snow, 16 inches of old, settled snow, or as little as 4 inches of solid ice - snow that heavy is rare here but ice from a freeze-thaw cycle adds up far faster than the depth suggests. This is a meaningful design load - most modern-code homes handle it fine, though an addition, a carport or a flat-roofed section can be a weak spot.
Arapahoe County, CO: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#526 of 2,758
- Colorado rank#3 of 24
- Population666,918
- Annual snowfall, NOAA normal42.7 in.
- FIPS08005
Arapahoe County by the numbers
Nationally that's #526 out of 2,758 rated counties, the top 19%; within Colorado alone, Arapahoe County ranks #3 of 24. Colorado counties average 17.7 psf; Arapahoe County runs 2.3 psf higher than that.
Arapahoe County, FIPS 08005, is home to 666,918 people near 39.6446°N 104.3317°W. Its 20 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.
Arapahoe County's snowfall, most winters
42.7 in. a year: that's Arapahoe County's NOAA 1991-2020 snowfall normal, measured at BYERS 5 ENE, CO US (12.7 mi away). See the density guide.
Before you rely on Arapahoe County's number
Treat the Arapahoe 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. Details: the calculation guide.