SEAC 2016 Colorado Design Snow Loads - Ground Snow Load Map for Front Range Jurisdictions

Colorado has no statewide ground snow load table. Each jurisdiction is responsible for setting its own design values, and many Front Range counties use the SEAC 2016 Colorado Design Snow Loads map as their reference. If you are looking up a snow load for a Jefferson County or Larimer County garage door project, this is the source.

What this source says

The Structural Engineers Association of Colorado (SEAC) published the 2016 Colorado Design Snow Loads as a statewide ground snow load map for engineering use. The publication provides:

Ground snow load values (in psf) for Colorado locations, based on meteorological data, elevation, and statistical analysis of historical snowfall, intended for use as the pg value in ASCE 7 snow load calculations.

The map gives a ground snow load value (pg) in pounds per square foot for locations across Colorado. Values are shown by geographic zone and elevation band. The Front Range shows values from 25 to 50 psf depending on location and elevation.

Important conversion for ASCE 7-22. The SEAC 2016 publication predates ASCE 7-22. Under ASCE 7-22, the ground snow load values from SEAC 2016 must be multiplied by 1.6 to produce the design ground snow load (pg) for use in ASCE 7-22 calculations. This conversion factor accounts for a change in the statistical return period used to set the design value. Structural engineers must apply this factor; it is not optional.

For example, a SEAC 2016 map value of 30 psf becomes 48 psf (30 × 1.6) as the design pg under ASCE 7-22. Denver's 2025 DRC sets 43 psf, which reflects this ASCE 7-22 update applied to the Denver location.

When it applies

Jefferson County projects. Jefferson County uses the SEAC 2016 map for ground snow load values. The county's design criteria page references this publication. Snow loads in Jefferson County vary significantly with elevation: lower elevations near the plains may be 25 to 30 psf (SEAC 2016 value), while mountain communities like Evergreen are considerably higher.

Larimer County projects. Larimer County also uses SEAC 2016 snow load data. Fort Collins and Loveland at lower elevations use values in the 20 to 30 psf range (SEAC 2016), while mountain areas of the county are much higher.

Roof snow load calculation. Ground snow load is not the same as roof snow load. Engineers convert ground snow load to roof snow load using ASCE 7-22 Chapter 7, which accounts for slope, exposure, and thermal factors. A garage roof typically sees a roof snow load of 60 to 80 percent of the design ground snow load.

Post-2024 structural design. Any structural design using ASCE 7-22 must apply the 1.6 conversion factor to SEAC 2016 values. Plans reviewed under the 2025 Denver or 2024 IBC/IRC must use ASCE 7-22, so the conversion is mandatory.

What this means for you

Do not use the raw SEAC 2016 map value in an ASCE 7-22 design. The 1.6 factor is required. A structural engineer skipping this step will produce an unconservative design that does not meet current code.

Know your elevation. Snow loads vary with elevation in Colorado more than any other variable. Two locations 10 miles apart at different elevations can have very different snow loads. The SEAC 2016 map accounts for this, but you need to know your project elevation to read the map correctly.

Garage roofs in mountain communities. An attached garage at 7,500 feet near Evergreen or Conifer (Jefferson County) faces a ground snow load far higher than a Denver garage. The structural header over the garage door opening must be sized for the actual ground snow load at that elevation, converted per ASCE 7-22.

G Brothers is familiar with the SEAC 2016 snow load values across the Front Range and can help connect you with a structural engineer for header sizing on challenging sites.

Full text and source

The 2016 Colorado Design Snow Loads document is available from SEAC at https://seacolorado.org/docs/2016-Colorado-Design-Snow-Loads.pdf.

The SEAC 2016 Colorado Design Snow Loads publication provides the ground snow load map used by many Front Range jurisdictions. Under ASCE 7-22, multiply SEAC 2016 values by 1.6. Confirm the required snow load with your local building department before starting structural design.

Want to put numbers to this? Use the interactive roof snow load calculator below, or open the full roof snow load calculator with examples and notes.