SnowLoadCheck

Keweenaw County, MI Roof Snow Load - 63 psf

Keweenaw County, MI: your roof's ASCE 7 snow number, in plain English

Very heavy
63 psf

Keweenaw County's roofs are built to hold 63 psf of snow, the ASCE 7-22 figure a permit reviewer checks first.

In depth, not weight: that's roughly 138.6 inches of fresh, light snow, 50.4 inches of old, settled snow, or as little as 12.6 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. This ranks among the highest mapped design loads in the country outside case-study terrain - roof snow removal and periodic structural inspection are standard practice here.

Keweenaw County, MI: quick facts

Keweenaw County by the numbers

Nationally that's #4 out of 2,758 rated counties, the top 1%; within Michigan alone, Keweenaw County ranks #1 of 70. That's 31.3 psf above Michigan's own county-average design load of 31.7 psf.

Keweenaw County, FIPS 26083, is home to 2,161 people near 47.3673°N 88.3513°W. Its 90 psf ground snow load figure is the map value; 63 psf is what a roof is actually designed for.

Keweenaw County's snowfall, most winters

132.3 in. a year: that's Keweenaw County's NOAA 1991-2020 snowfall normal, measured at BIG BAY 1NW, MI US (46.5 mi away). 46.5 mi is a real gap between Keweenaw County and its nearest reporting station, so local snowfall can diverge from this figure, especially near elevation changes. See the density guide.

Before you rely on Keweenaw County's number

Treat the Keweenaw 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.)