Utah

Statewide summary — confirm with your building department before designing

No value on this row was changed by this audit, but the ground snow load on it is untenable as a single number and should not be used. Utah writes its own ground snow loads into state law: Utah Code 15A-3-202 replaces the IRC snow figure with a table of ground snow loads for selected Utah locations, which gives 28 psf at Salt Lake City, 31 psf at Provo, 37 psf at Ogden, 21 psf at St George, 43 psf at Logan, 52 psf at Morgan, 57 psf at Coalville, 60 psf at Heber City and 67 psf at Monticello, and sends every other location to the Utah Snow Load Study for a site specific value. The stored 30 psf happens to bracket Salt Lake City and Provo but is below the adopted requirement at Ogden, Logan, Heber City and most of the Wasatch Back, and it is nowhere near what the mountain communities carry. No single scalar informs both the valley floor and the canyons, so this is reported rather than corrected. Seismic design category D is confirmed and is the most clearly correct seismic value in this group: the USGS ASCE 7-16 design maps service at Site Class D and Risk Category II returns 0.997 g at Salt Lake City, 0.931 g at Provo and 0.908 g at Ogden, so the entire Wasatch Front, which holds the large majority of Utah's population, is category D. Southern and eastern Utah are lower, at 0.476 g in St George, category C, and 0.211 g at Moab, category B. Wind speed of 115 mph and frost depth of 36 inches could not be checked against an adopted Utah table and are unverified; 36 inches is deeper than the 30 inches commonly used in the Salt Lake valley and so errs safe. Termite risk of slight corresponds to the IRC slight to moderate band, which fits southern Utah better than the northern valleys, where the none to slight band is the usual reading; this was left alone because no adopted Utah table was found to settle it. Winter design temperature is unestablished. Confirm your own lot with the local building official. Sources: https://le.utah.gov/xcode/Title15A/Chapter3/C15A-3-S202_2022050420220701.pdf and https://earthquake.usgs.gov/ws/building-codes/ SNOW LOAD AUDIT 2026-08-12 (physical design data pass). Utah is the one state in this region with a real, state-adopted, statewide ground snow load source, and the min and max on this row now come from it. Range set to 21 psf minimum and 429 psf maximum. Both are GROUND snow loads, not roof snow loads. The adoption chain was read end to end. Utah Code 15A-2-103 incorporates the 2024 International Building Code and the 2021 International Residential Code as the construction standards for the state, together with the statewide amendments in Chapter 3. Utah Code 15A-3-202(19), in the version effective 1 July 2026, deletes the IRC ground snow load figure and substitutes a Utah table, Table R301.2(3), Ground Snow Loads for Selected Locations in Utah, listing 29 cities and towns with a county, a ground snow load in pounds per square foot and an elevation in feet. Within that table the lowest values are 21 psf at Moab and at St. George and the highest is 67 psf at Monticello. Every figure recorded in the earlier audit on this row was re-checked against the statute text and all of them hold: Salt Lake City 28, Provo 31, Ogden 37, St. George 21, Logan 43, Morgan 52, Coalville 57, Heber City 60, Monticello 67. Other entries are Beaver 35, Brigham City 42, Castle Dale 32, Duchesne 39, Farmington 35, Fillmore 30, Junction 27, Kanab 25, Loa 37, Manila 26, Manti 37, Nephi 39, Panguitch 41, Parowan 32, Price 31, Randolph 50, Richfield 27, Tooele 35 and Vernal 39. A footnote applies each value at and below the cited elevation with a 100 foot tolerance. The reason the maximum on this row is 429 and not 67 is that the statute does not stop at the table. Footnote 3 to Table R301.2(3), and Utah Code 15A-3-202(20), which deletes IRC Section R301.6 and replaces it with a section headed Utah Snow Loads, both direct that for any Utah location not in the table the ground snow load be taken from Bean, Maguire and Sun, The Utah Snow Load Study, 2018, Utah State University, Paper 3589, citing the web address utahsnowload.usu.edu. That is an adoption by reference inside a Utah statute. It settles the question this audit was asked to settle: the Utah Snow Load Study is a state-adopted source, not a private university publication, and its values may be used here. This is the opposite of the Colorado situation on the neighbouring row. The state-adopted map publishes its own bounds and those bounds are what the min and max record. The Utah Ground Snow Load Map states that its predictions are bounded above and below, that the lower limit is 21 psf, set to meet the ASCE 7 minimum, and that the upper limit is set so that predictions are not allowed to extend beyond the highest 50-year station ground snow load, which it gives as approximately 429 psf, with the regions where the map is capped at 429 psf shown in black on the overlay. So under the source Utah has adopted, no Utah site returns less than 21 psf and none returns more than about 429 psf. Three cautions. The map values are 50-year ground snow load estimates with a 2 percent annual probability of exceedance, which is the allowable-stress ground snow load convention that matches the statutory table; they are not the strength-based ground snow loads introduced in ASCE 7-22, and no conversion was performed. The map dataset is dated 3 April 2018 and the map itself warns that elevations above 9,000 feet rest on few stations and can be over-conservative, and that capped or low-confidence results carry a warning on the generated report. And there is an internal inconsistency in the statute worth knowing about: subsection (19) creates the table as Table R301.2(3), while the replacement Section R301.6 in subsection (20) refers to the snow loads specified in Table R301.2(5b). Two table numbers, one table. Both provisions send everything not in the table to the same USU study, so the practical effect is unambiguous, but the cross-reference does not match and this audit did not resolve it. None of the four existing values were changed. Ground snow load 30 psf is left in place but is a poor single number: it is the adopted figure for Fillmore only, and the adopted Salt Lake City value is 28 psf. Seismic design category D stands as previously verified. Wind speed 115 mph and frost depth 36 inches remain unsourced against any Utah state instrument, and that is now a confirmed absence rather than an untested assumption: Utah Code 15A-3-202 was read in full and contains no amendment setting a wind speed and no amendment setting a frost line depth. Its only Chapter 4 footing amendments, to R403.1.6 and R403.1.6.1, concern anchorage, not depth.