Shiawassee County, MI Roof Snow Load - 21 psf
Shiawassee County, MI roof snow load, translated
A typical heated home in Shiawassee County is designed to carry 21 pounds per square foot of snow on its roof, per ASCE 7-22.
On a roof that means 46.2 in. of fresh snow, 16.8 in. once it packs down, or 4.2 in. of solid ice - three very different piles for the same load. 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.
Shiawassee County in numbers
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#429 of 2,758
- Michigan rank#54 of 70
- Population67,982
- Annual snowfall, NOAA normal38.3 in.
- FIPS26155
Where Shiawassee County ranks
#54 of 70 Michigan counties by design load, top 16% of 2,758 nationally - that's Shiawassee County's spot. Michigan counties average 31.7 psf; Shiawassee County runs 10.7 psf lower than that.
FIPS 26155, population 67,982, centered near 42.9515°N 84.1464°W. ASCE 7's underlying ground snow load here is 30 psf before the code's exposure and importance factors bring it to the 21 psf design figure above.
Shiawassee County: average annual snowfall
Shiawassee County sees about 38.3 in. of snow most winters, per the OWOSSO WWTP, MI US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Shiawassee 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. See the methodology guide.