Allen County, IN Roof Snow Load - 20 psf
Allen County, IN: your roof's ASCE 7 snow number, in plain English
Allen County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. 14 psf is what the ground-load formula alone gives; Allen County's 20 psf low-slope minimum (§7.3.4) beats it, so that figure is the one that governs on flat and low-pitch roofs.
In depth, not weight: that's roughly 44 inches of fresh, light snow, 16 inches of old, settled snow, or as little as 4 inches of solid ice - snow that heavy is rare here but ice from a freeze-thaw cycle adds up far faster than the depth suggests. This is a meaningful design load - most modern-code homes handle it fine, though an addition, a carport or a flat-roofed section can be a weak spot.
Allen County, IN: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#550 of 2,758
- Indiana rank#3 of 89
- Population399,295
- Annual snowfall, NOAA normal33.6 in.
- FIPS18003
Allen County by the numbers
Nationally that's #550 out of 2,758 rated counties, the top 20%; within Indiana alone, Allen County ranks #3 of 89. 19.3 psf is Indiana's typical county figure - Allen County beats it by 0.7 psf.
Allen County, FIPS 18003, is home to 399,295 people near 41.0919°N 85.0718°W. Its 20 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.
Allen County's snowfall, most winters
33.6 in. a year: that's Allen County's NOAA 1991-2020 snowfall normal, measured at FT WAYNE INTL AP, IN US (10.9 mi away). See the density guide.
Before you rely on Allen County's number
Treat the Allen County figure as a starting point, not a final answer: it assumes standard occupancy, a heated structure and a moderately sheltered site, per ASCE 7-22's own defaults. Exposed terrain, an unheated building or a steeper roof all shift the real number.
For a real application, skip the county number and go straight to the ASCE 7 Hazard Tool - enter your coordinates and it returns a site-specific figure a plan reviewer will recognize. See the methodology guide.