Callaway County, MO Roof Snow Load - 20 psf
How much snow is too much for a roof in Callaway County, MO?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Callaway County to carry. ASCE 7's low-slope-roof minimum (§7.3.4) raises the governing figure to 20 psf - higher than the 14 psf the ground-load formula alone would give, and the code says use the larger one.
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. 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.
Callaway County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#759 of 2,758
- Missouri rank#18 of 115
- Population45,126
- Annual snowfall, NOAA normal18.9 in.
- FIPS29027
How Callaway County compares
20 psf ranks #759 of 2,758 US counties with a mapped snow load (top 28%) - and #18 of 115 in Missouri. That's 1.4 psf above Missouri's own county-average design load of 18.6 psf.
Population 45,126 (FIPS 29027), roughly 38.8355°N 91.9234°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 Callaway County, MO
NOAA's 30-year normal for Callaway County: 18.9 in. of snow a year, from the FULTON, MO US station. (fresh vs. packed vs. ice explains why.)
What this Callaway 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.
Callaway 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.