Fire Hazard Severity Zone Map

Learn about South Pasadena’s Updated Fire Hazard Severity Zone Map

Community Meeting 1: Thursday, September 4, 2025 at 7 p.m.

Monterey Hills Elementary School, 1624 Via Del Rey, South Pasadena

Community Meeting 2: Tuesday, September 9, 2025 at 7 p.m.

Arroyo Vista Elementary School, 335 El Centro Street, South Pasadena

2025 Update to City of South Pasadena Fire Hazard Severity Zone Map

The City of South Pasadena is in the process of adopting a revised version of the local Fire Hazard Severity Zone (FHSZ) map, which identifies areas of the community at greatest threat of wildfires. Once adopted, residents living in these zones will have new state-mandated requirements to reduce the impact of wildfire. These updates are crucial to helping us plan, prepare, and protect our community.

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History of Fire Hazard Severity Zones

FHSZ’s came because of legislation arising out of lessons learned from major wildland fires. In 1980, the Panorama Fire, which began in San Bernardino County and was pushed by strong Santa Ana winds burned 28,800 acres, destroyed 325 structures, and experienced 4 fatalities. In the aftermath, the Governor passed Public Resource Code 4201, which mandated CAL FIRE to develop FHSZ’s in the State Responsibility Areas. Eleven years later, the Tunnel Fire in 1991, which is more widely known as the Oakland Hills Fire, devastated a community that was not previously identified as a hazard zone because it was in a Local Responsibility Area. This fire was significant because it became the deadliest fire to date. Although it only burned 1,520 acres, it destroyed 2,900 structures and was attributed to the death of 25 people.

This event prompted legislators to adopt AB-337 also known as the “Bates Bill”. This bill mandated the Director of CAL FIRE to assess FHSZ’s in Local Responsibility Areas and make recommendations to the local agencies for “Very High” Fire Hazard Severity Zones.

In 2021, new legislation, Senate Bill 63 (Stern), now requires the adoption of all three FHSZ classes in the Local Responsibility Area. Previously, only the “Very High” FHSZ’s were required for adoption in Local Responsibility Areas.

Government Codes

Public Resource Code 4202; The State Fire Marshal shall classify lands within State Responsibility Areas into Fire Hazard Severity Zones. Each zone shall embrace relatively homogeneous lands and shall be based on fuel loading, slope, fire weather, and other relevant factors present, including areas where winds have been identified by the department as a major cause of wildfire spread.

Government Code 51178; The State Fire Marshal shall identify areas in the state as Moderate, High, and Very High Fire Hazard Severity Zones based on consistent statewide criteria and based on the severity of fire hazard that is expected to prevail in those areas. Moderate, High, and Very High Fire Hazard Severity Zones shall be based on fuel loading, slope, fire weather, and other relevant factors including areas where winds have been identified by the Office of the State Fire Marshal as a major cause of wildfire spread.

The Fire Hazard Severity Zone map reflects “hazard,” not “risk”. The map is like flood zone maps, where lands are described in terms of the probability level of a particular area being inundated by floodwaters, and not specifically prescriptive impacts. “Hazard” is based on the physical conditions that create a likelihood and expected fire behavior over a 30 to 50-year period without considering mitigation measures such as home hardening, recent wildfire, or fuel reduction on efforts. “Risk” is the potential damage a fire can do to the area under existing conditions, accounting for any modifications such as fuel reduction projects, defensible space, and ignition resistant building construction.

Frequently Asked Questions

What are Fire Hazard Severity Zones?

The State Fire Marshal is mandated to classify lands within State Responsibility Areas into Fire Hazard Severity Zones (FHSZ). Fire Hazard Severity Zones fall into one of the following classifications:

Moderate (yellow)
High (orange)
Very High (red)

The California laws that require Fire Hazard Severity Zones include California Public Resources Code 4201-4204, California Code of Regulations Title 14, Section 1280 and California Government Code 51175-89.

Why is the FHSZ map being updated?

The local hazard map is being updated to more accurately reflect the zones in South Pasadena that are susceptible to wildfire. In 2022, the City of South Pasadena established a local Fire Hazard Severity Zone which was adopted by local ordinance. In 2025, Cal Fire adopted a separate FHSZ map of the region which did not account for South Pasadena’s local ordinance.

This new version of the FHSZ map consolidates these maps through overlay of State FHSZ and South Pasadena local ordinance.

What do Fire Hazard Severity Zones measure?

The Fire Hazard Severity Zone map evaluates “hazard,” not “risk”. The map is like flood zone maps, where lands are described in terms of the probability level of a particular area being inundated by floodwaters, and not specifically prescriptive of impacts. “Hazard” is based on the physical conditions that create a likelihood and expected fire behavior over a 30 to 50-year period without considering mitigation measures such as home hardening, recent wildfire, or fuel reduction efforts. “Risk” is the potential damage a fire can do to the area under existing conditions, accounting for any modifications such as fuel reduction projects, defensible space, and ignition resistant building construction.

What are the uses of Fire Hazard Severity Zones?

Answer: The zones are used for several purposes including to designate areas where California’s defensible space standards and wildland urban interface building codes are FREQUENTLY ASKED QUESTIONS ABOUT: 2024 Fire Hazard Severity Zones Fire Hazard Severity Zones Explained CAL FIRE – December 18, 2024 2024 FAQ Page 2 required. They can be a factor in real estate disclosure, and local governments may consider them in their general plan.

What are the key elements of the Fire Hazard Severity Zone model?

The fire hazard severity model for wildland fire has two key elements: probability of an area burning and expected fire behavior under extreme fuel and weather conditions. The zones reflect areas that have similar burn probabilities and fire behavior characteristics. The factors considered in determining fire hazard within wildland areas are fire history, flame length, terrain, local weather, and potential fuel over a 50-year period. Outside of wildlands, the model considers factors that might lead to buildings being threatened, including terrain, weather, urban vegetation cover, blowing embers, proximity to wildland, fire history, and fire hazard in nearby wildlands. FHSZs are not a structure loss model, as key information regarding structure ignition (such as roof type, etc.) is not included.

Will the new Fire Hazard Severity Zones affect my ability to get or maintain insurance? Insurance companies use risk models, which differ from hazard models, because they consider the susceptibility of a structure to damage from fire and other short-term factors that are not included in hazard modeling. It is unlikely that insurance risk models specifically call out Fire Hazard Severity Zones as a factor, but much of the same data that is used in the fire hazard severity zone model are likely included in the insurance companies’ risk models. However, insurance risk models incorporate many additional factors and factors that change more frequently than those included in state and local hazard mapping.

Resources

Cal Fire – Fire Hazard Severity Zones

Cal Fire – Examples of State Minimum Requirements

For additional questions and inquiries, please email us at fdinfo@southpasadenaca.gov.