Hamilton County, IA Roof Snow Load - 21 psf

How much snow is too much for a roof in Hamilton County, IA?

Picture it, not just weigh it: 46.2 in. if it's fresh powder, 16.8 in. once it settles, or a mere 4.2 in. if it's ice. 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.

Hamilton County in numbers

• Design roof snow load21 psf
• Ground snow load, ASCE 7 map30 psf
• National rank#462 of 2,758
• Iowa rank#37 of 99
• Population14,856
• Annual snowfall, NOAA normal32.9 in.
• FIPS19079

How Hamilton County compares

21 psf ranks #462 of 2,758 US counties with a mapped snow load (top 17%) - and #37 of 99 in Iowa. That's 0.7 psf below Iowa's own county-average design load of 21.7 psf.

Population 14,856 (FIPS 19079), roughly 42.3908°N 93.7091°W. The 30 psf ground snow load ASCE 7-22 maps here becomes 21 psf once the code's own design factors are applied.

Typical snowfall in Hamilton County, IA

NOAA's 30-year normal for Hamilton County: 32.9 in. of snow a year, from the WEBSTER CITY, IA US station. (fresh vs. packed vs. ice explains why.)

What this Hamilton County figure assumes

This is a county-level reference figure for a typical heated home built to Risk Category II (ordinary residential), on a partially exposed lot - the assumptions ASCE 7-22 itself treats as the default case. A steeper roof, a fully exposed hilltop lot, an unheated structure, or a higher risk category all change the actual number.

Hamilton County's permit office wants an address-specific figure, not this county average - the ASCE 7 Hazard Tool is free, takes under a minute, and outputs a PDF most reviewers accept. (How this figure is calculated.)