Jefferson County, AL Roof Snow Load - 5 psf
Jefferson County, AL: your roof's ASCE 7 snow number, in plain English
Jefferson County's roofs are built to hold 5 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. §7.3.4's low-slope minimum of 5 psf is what actually governs on a flat or low-pitch roof here - higher than the 3.5 psf the base ground-load formula gives.
In depth, not weight: that's roughly 11 inches of fresh, light snow, 4 inches of old, settled snow, or as little as 1 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 is a modest add-on to standard roof loading - ordinary residential construction carries it without extra bracing.
Jefferson County at a glance
- Design roof snow load5 psf
- Ground snow load, ASCE 7 map5 psf
- National rank#2,081 of 2,758
- Alabama rank#18 of 67
- Population664,744
- Annual snowfall, NOAA normal1.2 in.
- FIPS01073
Jefferson County by the numbers
Nationally that's #2,081 out of 2,758 rated counties, the top 75%; within Alabama alone, Jefferson County ranks #18 of 67. Alabama counties average 5.6 psf; Jefferson County runs 0.6 psf lower than that.
Jefferson County, FIPS 01073, is home to 664,744 people near 33.5534°N 86.8965°W. Its 5 psf ground snow load figure is the map value; 5 psf is what a roof is actually designed for.
Jefferson County's snowfall, most winters
1.2 in. a year: that's Jefferson County's NOAA 1991-2020 snowfall normal, measured at BESSEMER 3 WSW, AL US (12.7 mi away). See the density guide.
Before you rely on Jefferson County's number
Treat the Jefferson 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. See the methodology guide.