Dane County, WI Roof Snow Load - 21 psf

How much snow is too much for a roof in Dane County, WI?

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. 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.

Dane County, WI: quick facts

• Design roof snow load21 psf
• Ground snow load, ASCE 7 map30 psf
• National rank#387 of 2,758
• Wisconsin rank#57 of 72
• Population588,347
• Annual snowfall, NOAA normal51.8 in.
• FIPS55025

How Dane County compares

21 psf ranks #387 of 2,758 US counties with a mapped snow load (top 14%) - and #57 of 72 in Wisconsin. Wisconsin counties average 30.9 psf; Dane County runs 9.9 psf lower than that.

Population 588,347 (FIPS 55025), roughly 43.0675°N 89.4179°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 Dane County, WI

NOAA's 30-year normal for Dane County: 51.8 in. of snow a year, from the MADISON DANE RGNL AP, WI US station. (fresh vs. packed vs. ice explains why.)

What this Dane 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.

Dane 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.)