Sac County, IA Roof Snow Load - 21 psf
Sac County, IA: your roof's ASCE 7 snow number, in plain English
Sac County's roofs are built to hold 21 psf of snow, the ASCE 7-22 figure a permit reviewer checks first.
In depth, not weight: that's roughly 46.2 inches of fresh, light snow, 16.8 inches of old, settled snow, or as little as 4.2 inches of solid ice - snow that heavy is rare here but ice from a freeze-thaw cycle adds up far faster than the depth suggests. 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.
Sac County in numbers
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#472 of 2,758
- Iowa rank#41 of 99
- Population9,533
- Annual snowfall, NOAA normal30.9 in.
- FIPS19161
Sac County by the numbers
Nationally that's #472 out of 2,758 rated counties, the top 17%; within Iowa alone, Sac County ranks #41 of 99. 21.7 psf is Iowa's typical county figure - Sac County comes in 0.7 psf under it.
Sac County, FIPS 19161, is home to 9,533 people near 42.3875°N 95.1052°W. Its 30 psf ground snow load figure is the map value; 21 psf is what a roof is actually designed for.
Sac County's snowfall, most winters
30.9 in. a year: that's Sac County's NOAA 1991-2020 snowfall normal, measured at SAC CITY, IA US (6.9 mi away). See the density guide.
Before you rely on Sac County's number
Treat the Sac County figure as a starting point, not a final answer: it assumes standard occupancy, a heated structure and a moderately sheltered site, per ASCE 7-22's own defaults. Exposed terrain, an unheated building or a steeper roof all shift the real number.
For a real application, skip the county number and go straight to the ASCE 7 Hazard Tool - enter your coordinates and it returns a site-specific figure a plan reviewer will recognize. (How this figure is calculated.)