Napa County, CA Roof Snow Load - 0 psf

How much snow is too much for a roof in Napa County, CA?

Picture it, not just weigh it: 0 in. if it's fresh powder, 0 in. once it settles, or a mere 0 in. if it's ice. This county’s ground snow load maps to zero - snow load is not a driver of roof design here.

Napa County in numbers

• Design roof snow load0 psf
• Ground snow load, ASCE 7 map0 psf
• National rank#2,568 of 2,758
• California rank#34 of 41
• Population132,727
• Annual snowfall, NOAA normal0 in.
• FIPS06055

How Napa County compares

0 psf ranks #2,568 of 2,758 US counties with a mapped snow load (top 93%) - and #34 of 41 in California. 1.1 psf is California's typical county figure - Napa County comes in 1.1 psf under it.

Population 132,727 (FIPS 06055), roughly 38.5071°N 122.3259°W. The 0 psf ground snow load ASCE 7-22 maps here becomes 0 psf once the code's own design factors are applied.

Typical snowfall in Napa County, CA

NOAA's 30-year normal for Napa County: 0 in. of snow a year, from the SAINT HELENA, CA US station. (fresh vs. packed vs. ice explains why.)

What this Napa County figure assumes

This is a county-level reference figure for a typical heated home built to Risk Category II (ordinary residential), on a partially exposed lot - the assumptions ASCE 7-22 itself treats as the default case. A steeper roof, a fully exposed hilltop lot, an unheated structure, or a higher risk category all change the actual number.

Napa County's permit office wants an address-specific figure, not this county average - the ASCE 7 Hazard Tool is free, takes under a minute, and outputs a PDF most reviewers accept. (How this figure is calculated.)