SnowLoadCheck

Clinton County, IA Roof Snow Load - 20 psf

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

Moderate
20 psf

Clinton County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. The physics-based figure alone would be 17.5 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 20 psf for flat and low-pitch roofs here, which is the number that actually governs.

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.

Clinton County in numbers

Clinton County by the numbers

Nationally that's #750 out of 2,758 rated counties, the top 27%; within Iowa alone, Clinton County ranks #51 of 99. Iowa counties average 21.7 psf; Clinton County runs 1.7 psf lower than that.

Clinton County, FIPS 19045, is home to 46,015 people near 41.8981°N 90.5342°W. Its 25 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.

Clinton County's snowfall, most winters

28.7 in. a year: that's Clinton County's NOAA 1991-2020 snowfall normal, measured at DE WITT, IA US (6 mi away). See the density guide.

Before you rely on Clinton County's number

Treat the Clinton 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.