Mackinac County, MI Roof Snow Load - 49 psf
Mackinac County, MI: your roof's ASCE 7 snow number, in plain English
Mackinac County's roofs are built to hold 49 psf of snow, the ASCE 7-22 figure a permit reviewer checks first.
In depth, not weight: that's roughly 107.8 inches of fresh, light snow, 39.2 inches of old, settled snow, or as little as 9.8 inches of solid ice - snow that heavy is rare here but ice from a freeze-thaw cycle adds up far faster than the depth suggests. A serious structural load. Homes built before modern snow-load provisions, or with low-slope/flat roof sections, are the ones most worth having checked.
Mackinac County in numbers
- Design roof snow load49 psf
- Ground snow load, ASCE 7 map70 psf
- National rank#19 of 2,758
- Michigan rank#5 of 70
- Population11,144
- Annual snowfall, NOAA normal98.5 in.
- FIPS26097
Mackinac County by the numbers
Nationally that's #19 out of 2,758 rated counties, the top 1%; within Michigan alone, Mackinac County ranks #5 of 70. That's 17.3 psf above Michigan's own county-average design load of 31.7 psf.
Mackinac County, FIPS 26097, is home to 11,144 people near 46.1679°N 85.3038°W. Its 70 psf ground snow load figure is the map value; 49 psf is what a roof is actually designed for.
Mackinac County's snowfall, most winters
98.5 in. a year: that's Mackinac County's NOAA 1991-2020 snowfall normal, measured at TROUT LAKE 1SW, MI US (13.1 mi away). See the density guide.
Before you rely on Mackinac County's number
Treat the Mackinac County figure as a starting point, not a final answer: it assumes standard occupancy, a heated structure and a moderately sheltered site, per ASCE 7-22's own defaults. Exposed terrain, an unheated building or a steeper roof all shift the real number.
For a real application, skip the county number and go straight to the ASCE 7 Hazard Tool - enter your coordinates and it returns a site-specific figure a plan reviewer will recognize. (How this figure is calculated.)