Memorandum
Date: June 3, 2025
To: The Honorable Lake County Board of Supervisors
From: Mireya G. Turner, Community Development Director
Jack Smalley, Chief Building Official
Subject: PUBLIC HEARING - Consideration of Proposed Ordinance Designating Fire Hazard Severity Zones in the Local Responsibility Areas in the Unincorporated Lands of Lake County
Executive Summary: The Office of the State Fire Marshal (OSFM) is required to classify lands within State Responsibility Areas (SRA) into Fire Hazard Severity Zones (FHSZ) of Moderate, High, and Very High fire hazard severity based on consistent statewide criteria and based on the severity of fire hazard that is expected to prevail in those areas. In April of 2024, the FHSZ map for the state of California was adopted for the SRA.
Both the OSFM and CAL FIRE have now classified, evaluated, and recommended updates to the 2011 FHSZ in the LRA and released updated maps (Attachment 1) for a 90-day public review and comment period. The comment period started on April 12, 2025, with a press release issued by the Risk Reduction Authority (Attachment 2), with the maps available for review on the Ready.LakeCountyCA.gov website and at the Community Development Department (CDD). Public comment was received via email to CDD (Attachment 3).
What is new for this update is the incorporation of climate data. A 2-kilometer grid of climate data covering the years 2003-2018 has been used in this update. The previous model used stock
weather inputs across the state to calculate wildland fire intensity scores. The updated model will adjust fire intensity scores based on the most extreme fire weather at a given location considering temperature, humidity, and wind speed. In addition, ember transport has been modeled based on local distributions of observed wind speed and direction values instead of using a generic buffer distance for urban areas adjacent to wildlands.
This updated modeling also places an emphasis on the spread ...
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