McCone County, MT Roof Snow Load - 21 psf

How much snow is too much for a roof in McCone County, MT?

Picture it, not just weigh it: 46.2 in. if it's fresh powder, 16.8 in. once it settles, or a mere 4.2 in. if it's ice. 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.

McCone County in numbers

• Design roof snow load21 psf
• Ground snow load, ASCE 7 map30 psf
• National rank#489 of 2,758
• Montana rank#5 of 29
• Population1,717
• Annual snowfall, NOAA normal43.7 in.
• FIPS30055

How McCone County compares

21 psf ranks #489 of 2,758 US counties with a mapped snow load (top 18%) - and #5 of 29 in Montana. Montana counties average 19 psf; McCone County runs 2 psf higher than that.

Population 1,717 (FIPS 30055), roughly 47.6296°N 105.7572°W. The 30 psf ground snow load ASCE 7-22 maps here becomes 21 psf once the code's own design factors are applied.

Typical snowfall in McCone County, MT

NOAA's 30-year normal for McCone County: 43.7 in. of snow a year, from the GLASGOW WFO, MT US station. That station is far enough away (56.6 mi) that local snowfall - especially at a different elevation or near a lake - can run noticeably higher or lower than this figure. (fresh vs. packed vs. ice explains why.)

What this McCone County figure assumes

This is a county-level reference figure for a typical heated home built to Risk Category II (ordinary residential), on a partially exposed lot - the assumptions ASCE 7-22 itself treats as the default case. A steeper roof, a fully exposed hilltop lot, an unheated structure, or a higher risk category all change the actual number.

McCone County's permit office wants an address-specific figure, not this county average - the ASCE 7 Hazard Tool is free, takes under a minute, and outputs a PDF most reviewers accept. Details: the calculation guide.