SnowLoadCheck

Harrison County, IA Roof Snow Load - 20 psf

What ASCE 7 says about snow load in Harrison County

Moderate
20 psf

That's Harrison 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 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.

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

Harrison County at a glance

Where Harrison County's figure sits nationally

Out of 2,758 rated US counties, Harrison County sits at #1,037, the top 38% nationally - #76 of 99 within Iowa. Iowa counties average 21.7 psf; Harrison County runs 1.7 psf lower than that.

Near 41.6886°N 95.8271°W, FIPS 19085: Harrison County counts 14,626 residents and a 25 psf map value, which the code's own factors turn into 20 psf.

How much it actually snows in Harrison County

Most winters bring Harrison County roughly 28.7 in. of snow - NOAA's normal at LOGAN, IA US, 4 mi off. (fresh vs. packed vs. ice explains why.)

Read this before you rely on it

Harrison 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 Harrison County's county-wide figure. See the methodology guide.