Dukes County, MA Roof Snow Load - 20 psf
What ASCE 7 says about snow load in Dukes County
That's Dukes County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. ASCE 7's low-slope-roof minimum (§7.3.4) raises the governing figure to 20 psf - higher than the 17.5 psf the ground-load formula alone would give, and the code says use the larger one.
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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Dukes County at a glance
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#947 of 2,758
- Massachusetts rank#13 of 14
- Population21,061
- Annual snowfall, NOAA normal25.3 in.
- FIPS25007
Where Dukes County's figure sits nationally
Out of 2,758 rated US counties, Dukes County sits at #947, the top 34% nationally - #13 of 14 within Massachusetts. 27.6 psf is Massachusetts's typical county figure - Dukes County comes in 7.6 psf under it.
Near 41.381°N 70.7015°W, FIPS 25007: Dukes County counts 21,061 residents and a 25 psf map value, which the code's own factors turn into 20 psf.
How much it actually snows in Dukes County
Most winters bring Dukes County roughly 25.3 in. of snow - NOAA's normal at EDGARTOWN, MA US, 9.5 mi off. (fresh vs. packed vs. ice explains why.)
Read this before you rely on it
Dukes 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 Dukes County's county-wide figure. See the methodology guide.