Fallon County, MT Roof Snow Load - 21 psf

Fallon County, MT: your roof's ASCE 7 snow number, in plain English

In depth, not weight: that's roughly 46.2 inches of fresh, light snow, 16.8 inches of old, settled snow, or as little as 4.2 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. Modern-code homes carry a load like this without issue; an older addition, a carport, or any flat-roofed section is where it is worth checking first.

Fallon County at a glance

• Design roof snow load21 psf
• Ground snow load, ASCE 7 map30 psf
• National rank#483 of 2,758
• Montana rank#3 of 29
• Population2,946
• Annual snowfall, NOAA normal39.1 in.
• FIPS30025

Fallon County by the numbers

Nationally that's #483 out of 2,758 rated counties, the top 18%; within Montana alone, Fallon County ranks #3 of 29. That's 2 psf above Montana's own county-average design load of 19 psf.

Fallon County, FIPS 30025, is home to 2,946 people near 46.3182°N 104.4057°W. Its 30 psf ground snow load figure is the map value; 21 psf is what a roof is actually designed for.

Fallon County's snowfall, most winters

39.1 in. a year: that's Fallon County's NOAA 1991-2020 snowfall normal, measured at MARMARTH, ND US (23.2 mi away). See the density guide.

Before you rely on Fallon County's number

Treat the Fallon 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.