Frederick County, MD Roof Snow Load - 21 psf
What ASCE 7 says about snow load in Frederick County
That's Frederick 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.
Frederick County at a glance
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#399 of 2,758
- Maryland rank#1 of 21
- Population299,317
- Annual snowfall, NOAA normal27.5 in.
- FIPS24021
Where Frederick County's figure sits nationally
Out of 2,758 rated US counties, Frederick County sits at #399, the top 14% nationally - #1 of 21 within Maryland. 20.1 psf is Maryland's typical county figure - Frederick County beats it by 0.9 psf.
Near 39.4702°N 77.3976°W, FIPS 24021: Frederick County counts 299,317 residents and a 30 psf map value, which the code's own factors turn into 21 psf.
How much it actually snows in Frederick County
Most winters bring Frederick County roughly 27.5 in. of snow - NOAA's normal at EMMITSBURG 2 SE, MD US, 15.5 mi off. (fresh vs. packed vs. ice explains why.)
Read this before you rely on it
Frederick 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 Frederick County's county-wide figure. See the methodology guide.