Poweshiek County, IA Roof Snow Load - 20 psf
Poweshiek County, IA: your roof's ASCE 7 snow number, in plain English
Poweshiek County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. 17.5 psf is what the ground-load formula alone gives; Poweshiek 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.
In depth, not weight: that's roughly 44 inches of fresh, light snow, 16 inches of old, settled snow, or as little as 4 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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Poweshiek County at a glance
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#977 of 2,758
- Iowa rank#67 of 99
- Population18,454
- Annual snowfall, NOAA normal29.8 in.
- FIPS19157
Poweshiek County by the numbers
Nationally that's #977 out of 2,758 rated counties, the top 35%; within Iowa alone, Poweshiek County ranks #67 of 99. 21.7 psf is Iowa's typical county figure - Poweshiek County comes in 1.7 psf under it.
Poweshiek County, FIPS 19157, is home to 18,454 people near 41.6846°N 92.5229°W. Its 25 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.
Poweshiek County's snowfall, most winters
29.8 in. a year: that's Poweshiek County's NOAA 1991-2020 snowfall normal, measured at BROOKLYN, IA US (5.7 mi away). See the density guide.
Before you rely on Poweshiek County's number
Treat the Poweshiek 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. See the methodology guide.