SnowLoadCheck

Phelps County, MO Roof Snow Load - 20 psf

What ASCE 7 says about snow load in Phelps County

Moderate
20 psf

That's Phelps 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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.

Phelps County in numbers

Where Phelps County's figure sits nationally

Out of 2,758 rated US counties, Phelps County sits at #754, the top 27% nationally - #17 of 115 within Missouri. That's 1.4 psf above Missouri's own county-average design load of 18.6 psf.

Near 37.8663°N 91.7904°W, FIPS 29161: Phelps County counts 45,672 residents and a 20 psf map value, which the code's own factors turn into 20 psf.

How much it actually snows in Phelps County

Most winters bring Phelps County roughly 17.3 in. of snow - NOAA's normal at ROLLA MISSOURI S&T, MO US, 6.3 mi off. (fresh vs. packed vs. ice explains why.)

Read this before you rely on it

Phelps 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 Phelps County's county-wide figure. See the methodology guide.