SnowLoadCheck

Hamilton County, IL Roof Snow Load - 15 psf

Hamilton County, IL: your roof's ASCE 7 snow number, in plain English

Moderate
15 psf

Hamilton County's roofs are built to hold 15 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. Flat and low-pitch roofs in Hamilton County are actually governed by ASCE 7's §7.3.4 minimum of 15 psf, not the 10.5 psf the ground-load formula alone would produce.

In depth, not weight: that's roughly 33 inches of fresh, light snow, 12 inches of old, settled snow, or as little as 3 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.

Hamilton County, IL: quick facts

Hamilton County by the numbers

Nationally that's #1,575 out of 2,758 rated counties, the top 57%; within Illinois alone, Hamilton County ranks #97 of 102. That's 4.3 psf below Illinois's own county-average design load of 19.3 psf.

Hamilton County, FIPS 17065, is home to 7,818 people near 38.0852°N 88.539°W. Its 15 psf ground snow load figure is the map value; 15 psf is what a roof is actually designed for.

Hamilton County's snowfall, most winters

13.3 in. a year: that's Hamilton County's NOAA 1991-2020 snowfall normal, measured at MCLEANSBORO, IL US (0.2 mi away). See the density guide.

Before you rely on Hamilton County's number

Treat the Hamilton 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.