Ground snow loads for use in the United States of America can be queried from ASCE 7-16 or other state-specific ground snow maps. The following provides a discussion on where the ground snow data comes from.

Contiguous Lower 48 States

Ground snow loads for the majority of states in the lower 48 are derived from the ASCE 7-16 ground snow maps. These maps are only provided in printed (or pdf) format. To allow for querying, shapefiles were produced and are included with Fenix distributions. The ASCE 7 ground snow load map contains contours of elevation & snow load pairs. The first pair of values that an input elevation falls below will be used to report the ground snow load. If the elevation falls above the maximum elevation range provided in the contour map, a case study is required.

Idaho State

ASCE 7-16 Table 7.2-3 provides city-specific ground snow loads for Idaho. All other areas in Idaho are currently listed as “case study only.”

Montana State

ASCE 7-16 Table 7.2-4 provides city-specific ground snow loads for Montana. All other areas in Montana are currently listed as “case study only.”

Washington State

ASCE 7-16 Table 7.2-5 provides city-specific ground snow loads for Washington. All other areas in Washington are currently listed as “case study only.”

New Mexico State

ASCE 7-16 Table 7.2-6 provides city-specific ground snow loads for New Mexico. All other areas in New Mexico are currently listed as “case study only.”

Oregon State

ASCE 7-16 Table 7.2-7 provides city-specific ground snow loads for Oregon. All other areas in Oregon are currently listed as “case study only.”

New Hampshire State

ASCE 7-16 Table 7.2-8 provides city-specific ground snow loads for New Hampshire. All other areas in New Hampshire are currently listed as “case study only.”

Utah State

Snow loads for Utah are determined from the Prism database (https://www.usu.edu/utahsnowload/). A shapefile of the prism database utilizing a 3,350ft x 3,350ft grid is distributed with Fenix and queried for all locations within the Utah state boundary. The Prism data contains both an elevation and a ground snow load. A 100ft elevation tolerance is used when querying the data. If your project elevation is greater than 100ft above the Prism grid elevation, a case study is required.

Colorado State

Colorado uses a completely unique methodology for determining ground snow loads. Instead of providing a contour map of ground snow load values, a map of ‘k’ values is provided at https://seacolorado.org/docs/2016-Colorado-Design-Snow-Loads.pdf. These ‘k’ values, along with elevation of the site and location (either on the eastern slope of the Rockies or not) are used in the following equations to determine the ground snow load.

Eastern Slope, Altitude < 6,500ft

$p_g=max(10A-15, 30)psf$

Eastern Slope, Altitude ≥ 6,500ft

$p_g=max(\frac{k}{100}A^3, 50)psf$

Elsewhere

$p_g=max(\frac{k}{100}A^3, 25)psf$

Where:

$A=$Elevation, in thousands of feet

Michigan State