Isabella County, MI Roof Snow Load - 28 psf
Isabella County, MI roof snow load, translated
A typical heated home in Isabella County is designed to carry 28 pounds per square foot of snow on its roof, per ASCE 7-22.
On a roof that means 61.6 in. of fresh snow, 22.4 in. once it packs down, or 5.6 in. of solid ice - three very different piles for the same load. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Isabella County, MI: quick facts
- Design roof snow load28 psf
- Ground snow load, ASCE 7 map40 psf
- National rank#233 of 2,758
- Michigan rank#33 of 70
- Population65,072
- Annual snowfall, NOAA normal48.5 in.
- FIPS26073
Where Isabella County ranks
#33 of 70 Michigan counties by design load, top 8% of 2,758 nationally - that's Isabella County's spot. That's 3.7 psf below Michigan's own county-average design load of 31.7 psf.
FIPS 26073, population 65,072, centered near 43.6452°N 84.8394°W. ASCE 7's underlying ground snow load here is 40 psf before the code's exposure and importance factors bring it to the 28 psf design figure above.
Isabella County: average annual snowfall
Isabella County sees about 48.5 in. of snow most winters, per the GLADWIN, MI US station's 1991-2020 NOAA normal. 28.7 mi is a real gap between Isabella County and its nearest reporting station, so local snowfall can diverge from this figure, especially near elevation changes. See the density guide.
Read this before you use Isabella County's figure
The figure above assumes the case ASCE 7-22 treats as typical: a heated, ordinary-occupancy home on a partially exposed site. Change any of those - exposure, heating, roof pitch, occupancy category - and the real design number moves.
A building permit needs the number at your exact address, not the county average - the free ASCE 7 Hazard Tool returns that from your coordinates in about a minute and produces a PDF a plan reviewer will accept. (How this figure is calculated.)