Woodbury County, IA Roof Snow Load - 21 psf
Woodbury County, IA roof snow load, translated
A typical heated home in Woodbury County is designed to carry 21 pounds per square foot of snow on its roof, per ASCE 7-22.
On a roof that means 46.2 in. of fresh snow, 16.8 in. once it packs down, or 4.2 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.
Woodbury County in numbers
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#418 of 2,758
- Iowa rank#28 of 99
- Population107,257
- Annual snowfall, NOAA normal36 in.
- FIPS19193
Where Woodbury County ranks
#28 of 99 Iowa counties by design load, top 15% of 2,758 nationally - that's Woodbury County's spot. Iowa counties average 21.7 psf; Woodbury County runs 0.7 psf lower than that.
FIPS 19193, population 107,257, centered near 42.3932°N 96.0533°W. ASCE 7's underlying ground snow load here is 30 psf before the code's exposure and importance factors bring it to the 21 psf design figure above.
Woodbury County: average annual snowfall
Woodbury County sees about 36 in. of snow most winters, per the SIOUX CITY GATEWAY AP, IA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Woodbury 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. Details: the calculation guide.