SnowLoadCheck

Boone County, IA Roof Snow Load - 20 psf

Boone County, IA: your roof's ASCE 7 snow number, in plain English

Moderate
20 psf

Boone County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. Flat and low-pitch roofs in Boone County are actually governed by ASCE 7's §7.3.4 minimum of 20 psf, not the 17.5 psf the ground-load formula alone would produce.

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. 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.

Boone County in numbers

Boone County by the numbers

Nationally that's #895 out of 2,758 rated counties, the top 32%; within Iowa alone, Boone County ranks #59 of 99. That's 1.7 psf below Iowa's own county-average design load of 21.7 psf.

Boone County, FIPS 19015, is home to 26,729 people near 42.0386°N 93.9394°W. Its 25 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.

Boone County's snowfall, most winters

35.9 in. a year: that's Boone County's NOAA 1991-2020 snowfall normal, measured at BOONE, IA US (2.5 mi away). See the density guide.

Before you rely on Boone County's number

Treat the Boone 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.)