Carter County, MT Roof Snow Load - 21 psf
What ASCE 7 says about snow load in Carter County
That's Carter County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from.
Converted to something you can actually eyeball on a roof: about 46.2 in. of fresh powder, 16.8 in. once it settles and packs down, or just 4.2 in. if it's turned to ice. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Carter County at a glance
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#490 of 2,758
- Montana rank#6 of 29
- Population1,399
- Annual snowfall, NOAA normal50 in.
- FIPS30011
Where Carter County's figure sits nationally
Out of 2,758 rated US counties, Carter County sits at #490, the top 18% nationally - #6 of 29 within Montana. Montana counties average 19 psf; Carter County runs 2 psf higher than that.
Near 45.5168°N 104.5153°W, FIPS 30011: Carter County counts 1,399 residents and a 30 psf map value, which the code's own factors turn into 21 psf.
How much it actually snows in Carter County
Most winters bring Carter County roughly 50 in. of snow - NOAA's normal at RIDGEWAY 1 S, MT US, 3.4 mi off. (fresh vs. packed vs. ice explains why.)
Read this before you rely on it
Carter County's number above is ASCE 7-22's default case, not a custom calculation: ordinary residential occupancy, heated, sited on ground that's neither fully sheltered nor fully exposed. Any one of those changing - pitch, exposure, heating, occupancy - moves the real figure.
Nothing here substitutes for an address-level number. Get one free, in about a minute, from the ASCE 7 Hazard Tool using your own coordinates rather than Carter County's county-wide figure. See the methodology guide.