You may be aware of updates to the model codes approved by the American Society of Civil Engineers in ASCE 7-22 and adopted in the 2024 IBC.  As a result of these changes, the 2024 CBC relies on a new national geodatabase and a new methodology to determine building standards applicable to natural hazard risks, including ground snow loads.

Snow conditions on building sites within California’s mountainous regions can vary significantly, due to extreme topography and unique wind and solar impacts.  Consequently, building sites located close to one another may experience different snow loads. For this reason, since the inception of ASCE 7 in 1995, the CBC has authorized local Building Officials in California’s mountainous regions to use site-specific “case studies,” based on objective data, to determine ground snow load requirements. 

The new ASCE 7-22 geodatabase includes ground snow load values for sites in jurisdictions that have previously relied on case studies to determine ground snow loads for specific projects. In many cases, the results of the geodatabase indicate significant increases in minimum ground snow load requirements for sites across California’s mountainous regions. In some cases, requirements have increased by more than 100%.

ASCE 7-22 states that “where the results from the geodatabase indicate that a case study needs to be conducted for a specific location, the ground snow load determination for the location shall be based on an analysis of data available in the vicinity of the site, …approved by the Authority Having Jurisdiction.”  Nonetheless, some uncertainty remains as to whether local California Building Officials in mountainous regions may continue to conduct site-specific case studies to determine snow load requirements.

As always, CALBO seeks to reduce uncertainty and ensure consistency among jurisdictions. CALBO recognizes that the ASCE 7-22 geodatabase is an important tool to determine ground snow load requirements in most jurisdictions in California.  However, empirical evidence to date demonstrates that existing case study methods to determine ground snow load requirements are efficient and effective to promote building and public safety.  Therefore, CALBO supports the continued use of site-specific case studies in California’s mountainous regions.[*]

Should your jurisdiction have concerns with the impact of the 2024 CBC on ground snow load requirements, or CBC 1608.2, please consult your City Attorney or County Counsel accordingly. 

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[*] In addition, local Building Officials’ authority under 2024 CBC 1.8.7 is unchanged from prior code cycles.