Lawrence County, SD Roof Snow Load - 20 psf
How much snow is too much for a roof in Lawrence County, SD?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Lawrence County to carry. 17.5 psf is what the ground-load formula alone gives; Lawrence 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.
Lawrence County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#872 of 2,758
- South Dakota rank#59 of 65
- Population28,809
- Annual snowfall, NOAA normal183.9 in.
- FIPS46081
How Lawrence County compares
20 psf ranks #872 of 2,758 US counties with a mapped snow load (top 32%) - and #59 of 65 in South Dakota. South Dakota counties average 28.2 psf; Lawrence County runs 8.2 psf lower than that.
Population 28,809 (FIPS 46081), roughly 44.3485°N 103.8064°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 Lawrence County, SD
NOAA's 30-year normal for Lawrence County: 183.9 in. of snow a year, from the LEAD, SD US station. (fresh vs. packed vs. ice explains why.)
What this Lawrence 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.
Lawrence 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.