SnowLoadCheck

Alleghany County, NC Roof Snow Load - 20 psf

What ASCE 7 says about snow load in Alleghany County

Moderate
20 psf

That's Alleghany County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. The physics-based figure alone would be 14 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 20 psf for flat and low-pitch roofs here, which is the number that actually governs.

Converted to something you can actually eyeball on a roof: about 44 in. of fresh powder, 16 in. once it settles and packs down, or just 4 in. if it's turned to ice. This is a meaningful design load - most modern-code homes handle it fine, though an addition, a carport or a flat-roofed section can be a weak spot.

Alleghany County, NC: quick facts

Where Alleghany County's figure sits nationally

Out of 2,758 rated US counties, Alleghany County sits at #1,082, the top 39% nationally - #8 of 100 within North Carolina. 12.9 psf is North Carolina's typical county figure - Alleghany County beats it by 7.1 psf.

Near 36.4894°N 81.1323°W, FIPS 37005: Alleghany County counts 11,379 residents and a 20 psf map value, which the code's own factors turn into 20 psf.

How much it actually snows in Alleghany County

Most winters bring Alleghany County roughly 18.6 in. of snow - NOAA's normal at SPARTA 3.5 SSW, NC US, 2.4 mi off. (fresh vs. packed vs. ice explains why.)

Read this before you rely on it

Alleghany 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 Alleghany County's county-wide figure. Details: the calculation guide.