Carroll County, MO Roof Snow Load - 20 psf
Carroll County, MO roof snow load, translated
A typical heated home in Carroll County is designed to carry 20 pounds per square foot of snow on its roof, per ASCE 7-22. 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.
On a roof that means 44 in. of fresh snow, 16 in. once it packs down, or 4 in. of solid ice - three very different piles for the same load. 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.
Carroll County, MO: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#1,143 of 2,758
- Missouri rank#70 of 115
- Population8,414
- Annual snowfall, NOAA normal12.7 in.
- FIPS29033
Where Carroll County ranks
#70 of 115 Missouri counties by design load, top 41% of 2,758 nationally - that's Carroll County's spot. That's 1.4 psf above Missouri's own county-average design load of 18.6 psf.
FIPS 29033, population 8,414, centered near 39.4274°N 93.5002°W. ASCE 7's underlying ground snow load here is 20 psf before the code's exposure and importance factors bring it to the 20 psf design figure above.
Carroll County: average annual snowfall
Carroll County sees about 12.7 in. of snow most winters, per the CARROLLTON, MO US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Carroll County's figure
The figure above assumes the case ASCE 7-22 treats as typical: a heated, ordinary-occupancy home on a partially exposed site. Change any of those - exposure, heating, roof pitch, occupancy category - and the real design number moves.
A building permit needs the number at your exact address, not the county average - the free ASCE 7 Hazard Tool returns that from your coordinates in about a minute and produces a PDF a plan reviewer will accept. See the methodology guide.