McNairy County, TN Roof Snow Load - 10 psf
McNairy County, TN: your roof's ASCE 7 snow number, in plain English
McNairy County's roofs are built to hold 10 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. ASCE 7's low-slope-roof minimum (§7.3.4) raises the governing figure to 10 psf - higher than the 7 psf the ground-load formula alone would give, and the code says use the larger one.
In depth, not weight: that's roughly 22 inches of fresh, light snow, 8 inches of old, settled snow, or as little as 2 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 modest addition to standard roof loading. Ordinary residential construction handles this without extra bracing.
McNairy County in numbers
- Design roof snow load10 psf
- Ground snow load, ASCE 7 map10 psf
- National rank#1,870 of 2,758
- Tennessee rank#59 of 95
- Population26,103
- Annual snowfall, NOAA normal1 in.
- FIPS47109
McNairy County by the numbers
Nationally that's #1,870 out of 2,758 rated counties, the top 68%; within Tennessee alone, McNairy County ranks #59 of 95. Tennessee counties average 10.3 psf; McNairy County runs 0.3 psf lower than that.
McNairy County, FIPS 47109, is home to 26,103 people near 35.1754°N 88.5637°W. Its 10 psf ground snow load figure is the map value; 10 psf is what a roof is actually designed for.
McNairy County's snowfall, most winters
1 in. a year: that's McNairy County's NOAA 1991-2020 snowfall normal, measured at SELMER, TN US (2.1 mi away). See the density guide.
Before you rely on McNairy County's number
Treat the McNairy 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. Details: the calculation guide.