Crawford County, IA Roof Snow Load - 20 psf
How much snow is too much for a roof in Crawford County, IA?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Crawford County to carry. §7.3.4's low-slope minimum of 20 psf is what actually governs on a flat or low-pitch roof here - higher than the 17.5 psf the base ground-load formula gives.
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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Crawford County, IA: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#1,006 of 2,758
- Iowa rank#72 of 99
- Population16,378
- Annual snowfall, NOAA normal34.5 in.
- FIPS19047
How Crawford County compares
20 psf ranks #1,006 of 2,758 US counties with a mapped snow load (top 36%) - and #72 of 99 in Iowa. That's 1.7 psf below Iowa's own county-average design load of 21.7 psf.
Population 16,378 (FIPS 19047), roughly 42.0431°N 95.3891°W. The 25 psf ground snow load ASCE 7-22 maps here becomes 20 psf once the code's own design factors are applied.
Typical snowfall in Crawford County, IA
NOAA's 30-year normal for Crawford County: 34.5 in. of snow a year, from the DENISON, IA US station. (fresh vs. packed vs. ice explains why.)
What this Crawford 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.
Crawford 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.