Montgomery County, PA Roof Snow Load - 21 psf
What ASCE 7 says about snow load in Montgomery County
That's Montgomery 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.
Montgomery County in numbers
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#383 of 2,758
- Pennsylvania rank#4 of 38
- Population879,190
- Annual snowfall, NOAA normal12.9 in.
- FIPS42091
Where Montgomery County's figure sits nationally
Out of 2,758 rated US counties, Montgomery County sits at #383, the top 14% nationally - #4 of 38 within Pennsylvania. That's 0.1 psf above Pennsylvania's own county-average design load of 20.9 psf.
Near 40.21°N 75.3702°W, FIPS 42091: Montgomery County counts 879,190 residents and a 30 psf map value, which the code's own factors turn into 21 psf.
How much it actually snows in Montgomery County
Most winters bring Montgomery County roughly 12.9 in. of snow - NOAA's normal at GRATERFORD 1 E, PA US, 3.1 mi off. (fresh vs. packed vs. ice explains why.)
Read this before you rely on it
Montgomery 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 Montgomery County's county-wide figure. Details: the calculation guide.