Minnesota

Statewide summary — confirm with your building department before designing

AUDIT 2026-08-12 (physical design data pass). Minnesota is one of the few states that legislates a ground snow load outright, and the range on this row is now taken from the rule rather than from a hazard map. Minnesota Rules part 1303.1700, titled Ground Snow Load, provides in full that the ground snow load, Pg, to be used in determining the design snow loads for buildings and other structures shall be 60 pounds per square foot in Aitkin, Becker, Beltrami, Carlton, Cass, Clearwater, Cook, Crow Wing, Hubbard, Itasca, Kanabec, Kittson, Koochiching, Lake, Lake of the Woods, Mahnomen, Marshall, Mille Lacs, Morrison, Norman, Otter Tail, Pennington, Pine, Polk, Red Lake, Roseau, St. Louis, Todd and Wadena, and 50 pounds per square foot in all other counties. That is 29 counties at 60 psf and the remaining 58 at 50 psf, so the statewide minimum is 50 and the statewide maximum is 60. These are ground loads, explicitly so named in the rule, not roof loads. The Department of Labor and Industry publishes a county map of the same two zones, headed SNOW LOAD MSBC RULES 1303.1700 table R301.2(1); the map was rendered and read county by county and agrees with the rule text, including the counties most likely to disagree - Clay, Wilkin, Grant, Douglas and Traverse all fall below the line at 50 psf on the map and are all absent from the rule 60 psf list. No conflict between the two official sources was found. Wind speed corrected from 105 to 115 mph. Minnesota Rules part 1309.0301, subpart 2, replaces IRC Table R301.2(1) outright, and the replacement table states 115 mph in the wind speed column, YES for topographic effects, A for seismic design category, Severe for weathering, and Yes for ice barrier underlayment. 115 mph is therefore a state-adopted ultimate design wind speed, not an interpolation off a national contour map, and the previous 105 understated it. Subpart 3 of the same part deletes IRC Figure R301.2(6), the national ground snow load map, in its entirety, so within Minnesota the part 1303.1700 county values are the only ground snow loads with legal force. The roof snow load cell of the Minnesota table is filled with the formula pf = 0.7 x pg rather than a number, which yields 42 psf on the roof in the 60 psf counties and 35 psf in the 50 psf counties. Seismic design category A is confirmed as a state-published value rather than a computed one; it is written into the Minnesota version of Table R301.2(1), with footnote l explaining that it is assigned to allow the application of the least restrictive topographic provisions of the code. Frost depth 42 inches is confirmed against part 1303.1600, but the county counts in the earlier note were wrong and are corrected here. The rule sets a minimum footing depth of five feet in Zone I and three and one-half feet, that is 42 inches, in Zone II. Zone I is 34 counties, not 33: Aitkin, Becker, Beltrami, Carlton, Cass, Clay, Clearwater, Cook, Crow Wing, Douglas, Grant, Hubbard, Itasca, Kanabec, Kittson, Koochiching, Lake, Lake of the Woods, Mahnomen, Marshall, Mille Lacs, Morrison, Norman, Otter Tail, Pennington, Pine, Polk, Red Lake, Roseau, St. Louis, Todd, Traverse, Wadena and Wilkin. Zone II is 53 counties, not 48, and the two lists together account for all 87 Minnesota counties. Note that the frost zones and the snow zones are not the same partition: Clay, Douglas, Grant, Traverse and Wilkin require the deeper five-foot footing but carry the lower 50 psf ground snow load. Check your county against both parts separately. PRIOR AUDIT NOTE (retained; its statement that no value other than frost depth was changed is superseded by the wind speed correction above, and its county counts are corrected above): Frost depth corrected from 60 to 42 inches by audit. Minnesota Rules part 1303.1600 divides the state into two footing depth zones. Zone II, at 42 inches, covers 48 southern and central counties including Hennepin, Ramsey, Dakota, Anoka, Washington, Scott, Carver, Olmsted and Stearns, which is the entire Twin Cities metropolitan area, Rochester and St Cloud and roughly three quarters of the state population. Zone I, at 60 inches, covers 33 northern counties including St. Louis, Beltrami, Otter Tail, Crow Wing, Itasca, Cass and Polk. The stored 60 inches was the Zone I figure applied statewide and would have sent a Twin Cities builder 18 inches deeper than the rule requires. Confirm your county against part 1303.1600 before excavating. No other value on this row was changed. Ground snow load 50 psf is correct for almost all of Minnesota under ASCE 7-16, including Minneapolis, Rochester, St Cloud, Moorhead and International Falls; the Lake Superior shore around Duluth is 60 psf. Seismic design category A holds throughout Minnesota, which has the lowest mapped seismic hazard in this data set. Wind speed 105 mph is the ASCE 7-16 interior base contour for ultimate design wind speed at Risk Category II; Minnesota site values run about 106 to 111 mph, rising toward the western border, so 110 mph is the conservative reading. The winter design temperature is ASHRAE data, is not fixed by Minnesota Rules, and is unverified.