St. Louis County, MN Roof Snow Load - 49 psf
St. Louis County, MN: your roof's ASCE 7 snow number, in plain English
St. Louis County's roofs are built to hold 49 psf of snow, the ASCE 7-22 figure a permit reviewer checks first.
In depth, not weight: that's roughly 107.8 inches of fresh, light snow, 39.2 inches of old, settled snow, or as little as 9.8 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 serious structural load - older homes built before modern snow-load provisions, or ones with low-slope or flat roof sections, are worth having checked.
Already snow on the roof in St. Louis County?
St. Louis County in numbers
- Design roof snow load49 psf
- Ground snow load, ASCE 7 map70 psf
- National rank#9 of 2,758
- Minnesota rank#1 of 87
- Population200,794
- Annual snowfall, NOAA normal83.9 in.
- FIPS27137
St. Louis County by the numbers
Nationally that's #9 out of 2,758 rated counties, the top 1%; within Minnesota alone, St. Louis County ranks #1 of 87. That's 11.6 psf above Minnesota's own county-average design load of 37.4 psf.
St. Louis County, FIPS 27137, is home to 200,794 people near 47.5786°N 92.5146°W. Its 70 psf ground snow load figure is the map value; 49 psf is what a roof is actually designed for.
St. Louis County's snowfall, most winters
83.9 in. a year: that's St. Louis County's NOAA 1991-2020 snowfall normal, measured at BABBITT, MN US (27.7 mi away). Worth noting: the nearest station reporting snowfall normals sits 27.7 mi from St. Louis County's center, so treat this as a regional figure rather than an exact one. See the density guide.
Before you rely on St. Louis County's number
Treat the St. Louis 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. Details: the calculation guide.