SnowLoadCheck

Clay County, IL Roof Snow Load - 20 psf

What ASCE 7 says about snow load in Clay County

Moderate
20 psf

That's Clay County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. 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.

Converted to something you can actually eyeball on a roof: about 44 in. of fresh powder, 16 in. once it settles and packs down, or just 4 in. if it's turned to ice. 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.

Snow on Clay County's roofs right now?

in. of

Clay County in numbers

Where Clay County's figure sits nationally

Out of 2,758 rated US counties, Clay County sits at #1,060, the top 38% nationally - #72 of 102 within Illinois. Illinois counties average 19.3 psf; Clay County runs 0.7 psf higher than that.

Near 38.7468°N 88.4823°W, FIPS 17025: Clay County counts 12,821 residents and a 20 psf map value, which the code's own factors turn into 20 psf.

How much it actually snows in Clay County

Most winters bring Clay County roughly 8.3 in. of snow - NOAA's normal at FLORA 5 NW, IL US, 5.6 mi off. (fresh vs. packed vs. ice explains why.)

Read this before you rely on it

Clay County's number above is ASCE 7-22's default case, not a custom calculation: ordinary residential occupancy, heated, sited on ground that's neither fully sheltered nor fully exposed. Any one of those changing - pitch, exposure, heating, occupancy - moves the real figure.

Nothing here substitutes for an address-level number. Get one free, in about a minute, from the ASCE 7 Hazard Tool using your own coordinates rather than Clay County's county-wide figure. See the methodology guide.