Lee County, IA Roof Snow Load - 20 psf
How much snow is too much for a roof in Lee County, IA?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Lee County to carry. 14 psf is what the ground-load formula alone gives; Lee 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.
Lee County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#851 of 2,758
- Iowa rank#58 of 99
- Population32,376
- Annual snowfall, NOAA normal26.6 in.
- FIPS19111
How Lee County compares
20 psf ranks #851 of 2,758 US counties with a mapped snow load (top 31%) - and #58 of 99 in Iowa. That's 1.7 psf below Iowa's own county-average design load of 21.7 psf.
Population 32,376 (FIPS 19111), roughly 40.6476°N 91.4772°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 Lee County, IA
NOAA's 30-year normal for Lee County: 26.6 in. of snow a year, from the DONNELLSON, IA US station. (fresh vs. packed vs. ice explains why.)
What this Lee 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.
Lee 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.