Cassia County, ID Roof Snow Load - 10 psf
Cassia County, ID: your roof's ASCE 7 snow number, in plain English
Cassia County's roofs are built to hold 10 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. §7.3.4's low-slope minimum of 10 psf is what actually governs on a flat or low-pitch roof here - higher than the 7 psf the base ground-load formula gives.
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. This is a modest add-on to standard roof loading - ordinary residential construction carries it without extra bracing.
Cassia County in numbers
- Design roof snow load10 psf
- Ground snow load, ASCE 7 map10 psf
- National rank#1,872 of 2,758
- Idaho rank#7 of 9
- Population25,976
- Annual snowfall, NOAA normal24.2 in.
- FIPS16031
Cassia County by the numbers
Nationally that's #1,872 out of 2,758 rated counties, the top 68%; within Idaho alone, Cassia County ranks #7 of 9. That's 2.2 psf below Idaho's own county-average design load of 12.2 psf.
Cassia County, FIPS 16031, is home to 25,976 people near 42.2823°N 113.6263°W. Its 10 psf ground snow load figure is the map value; 10 psf is what a roof is actually designed for.
Cassia County's snowfall, most winters
24.2 in. a year: that's Cassia County's NOAA 1991-2020 snowfall normal, measured at TWIN FALLS 6 E, ID US (41 mi away). 41 mi is a real gap between Cassia 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 Cassia County's number
Treat the Cassia 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.