SnowLoadCheck

Randolph County, IL Roof Snow Load - 20 psf

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

Moderate
20 psf

Randolph 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 14 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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.

Randolph County at a glance

Randolph County by the numbers

Nationally that's #862 out of 2,758 rated counties, the top 31%; within Illinois alone, Randolph County ranks #44 of 102. 19.3 psf is Illinois's typical county figure - Randolph County beats it by 0.7 psf.

Randolph County, FIPS 17157, is home to 29,903 people near 38.0565°N 89.8212°W. Its 20 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.

Randolph County's snowfall, most winters

4.3 in. a year: that's Randolph County's NOAA 1991-2020 snowfall normal, measured at KASKASKIA RVR NAVIGATION LOCK, IL US (8.5 mi away). See the density guide.

Before you rely on Randolph County's number

Treat the Randolph 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.)