Blair County, PA Roof Snow Load - 21 psf
Blair County, PA roof snow load, translated
A typical heated home in Blair County is designed to carry 21 pounds per square foot of snow on its roof, per ASCE 7-22.
On a roof that means 46.2 in. of fresh snow, 16.8 in. once it packs down, or 4.2 in. of solid ice - three very different piles for the same load. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Blair County at a glance
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#415 of 2,758
- Pennsylvania rank#12 of 38
- Population120,269
- Annual snowfall, NOAA normal25.7 in.
- FIPS42013
Where Blair County ranks
#12 of 38 Pennsylvania counties by design load, top 15% of 2,758 nationally - that's Blair County's spot. 20.9 psf is Pennsylvania's typical county figure - Blair County beats it by 0.1 psf.
FIPS 42013, population 120,269, centered near 40.4987°N 78.3096°W. ASCE 7's underlying ground snow load here is 30 psf before the code's exposure and importance factors bring it to the 21 psf design figure above.
Blair County: average annual snowfall
Blair County sees about 25.7 in. of snow most winters, per the WILLIAMSBURG, PA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Blair County's figure
The figure above assumes the case ASCE 7-22 treats as typical: a heated, ordinary-occupancy home on a partially exposed site. Change any of those - exposure, heating, roof pitch, occupancy category - and the real design number moves.
A building permit needs the number at your exact address, not the county average - the free ASCE 7 Hazard Tool returns that from your coordinates in about a minute and produces a PDF a plan reviewer will accept. Details: the calculation guide.