Pursuant to 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.

Pursuant to 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.Per 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.This feature service represents Fire Hazard Severity Zones (FHSZ) in State Responsibility Area (SRA) as effective April 1, 2024. FHSZ that was adopted as SRA in 2007 and due to regulatory processes are no longer classified as SRA have become classified as LRA. This map combines these areas with FHSZ maps recommended in LRA from 2007-2011. This should be considered an interim combination dataset until new FHSZ are mapped in LRA.

PRC 4201 - 4204 and Govt. Code 51175-89 direct the California Department of Forestry and Fire Protection (CAL FIRE) to map areas of significant fire hazards based on fuels, terrain, weather, and other relevant factors. These zones, referred to as Fire Hazard Severity Zones (FHSZ), define the application of various mitigation strategies to reduce risk associated with wildland fires.

CAL FIRE is remapping Fire Hazard Severity Zones (FHSZ) for State Responsibility Areas (SRA) and Very High Fire Hazard Severity Zones (VHFHSZ) in Local Responsibility Areas (LRA) to provide updated map zones, based on new data, science, and technology.

This specific dataset provides DRAFT boundaries for Very High FHSZs within LRA lands. Since these zones were the result of a model that considers influence of fire behavior and embers from adjacent lands, zones for SRA and FRA lands are included to assist in understanding the hazard zoning on LRA lands.

Draft maps are available at: http://frap.cdf.ca.gov/projects/hazard/fhz.html

More information about the project can be found at: http://frap.cdf.ca.gov/projects/hazard/hazard.html

On October 30, 2015 Governor Brown issued an emergency declaration requiring public agencies to identify areas of tree mortality that hold the greatest potential to result in wildfire and/or falling trees and threaten people and property in these areas. Once identified, these areas will be prioritized for removal of dead and dying trees that present a threat to public safety.

Wildfire - Fire Risk and Fire Responsibility Areas (CAL FIRE) for development of the Parcel Inventory dataset for the Housing Element Site Selection (HESS) Pre-Screening Tool.

** This data set represents Moderate, High, and Very High Fire Hazard Severity Zones in State Responsibility Areas (SRA) and Very High Fire Hazard Severity Zones in Local Responsibility Areas (LRA) for the San Francisco Bay Region and some of its surrounding counties. The data was assembled by the Metropolitan Transportation Commission from multiple shapefiles provided by the California Department of Forestry and Fire Protection. The SRA data was extracted from a statewide shapefile and the LRA data is a combination of county shapefiles. All source data was downloaded from the Office of the State Fire Marshal's Fire Hazard Severity Zones Maps page (https://osfm.fire.ca.gov/divisions/community-wildfire-preparedness-and-mitigation/wildland-hazards-building-codes/fire-hazard-severity-zones-maps/). **

State Responsibility Areas PRC 4201 - 4204 and Govt. Code 51175-89 direct CAL FIRE to map areas of significant fire hazards based on fuels, terrain, weather, and other relevant factors. These zones, referred to as Fire Hazard Severity Zones (FHSZ), define the application of various mitigation strategies to reduce risk associated with wildland fires.

CAL FIRE is remapping FHSZ for SRA and Very High Fire Hazard Severity Zones (VHFHSZ) recommendations in LRA to provide updated map zones, based on new data, science, and technology.

Local Responsibility Areas Government Code 51175-89 directs the CAL FIRE to identify areas of very high fire hazard severity zones within LRA. Mapping of the areas, referred to as VHFHSZ, is based on data and models of, potential fuels over a 30-50 year time horizon and their associated expected fire behavior, and expected burn probabilities to quantify the likelihood and nature of vegetation fire exposure (including firebrands) to buildings. Details on the project and specific modeling methodology can be found at https://frap.cdf.ca.gov/projects/hazard/methods.html. Local Responsibility Area VHFHSZ maps were initially developed in the mid-1990s and are now being updated based on improved science, mapping techniques, and data.

Local government had 120 days to designate, by ordinance, very high fire hazard severity zones within their jurisdiction after receiving the CAL FIRE recommendations. Local governments were able to add additional VHFHSZs. There was no requirement for local government to report their final action to CAL FIRE when the recommended zones are adopted. Consequently, users are directed to the appropriate local entity (county, city, fire department, or Fire Protection District) to determine the status of the local fire hazard severity zone ordinance.

In late 2005, to be effective in 2008, the California Building Commission adopted California Building Code Chapter 7A requiring new buildings in VHFHSZs to use ignition resistant construction methods and materials. These new codes include provisions to improve the ignition resistance of buildings, especially from firebrands. The updated very high fire hazard severity zones will be used by building officials for new building permits in LRA. The updated zones will also be used to identify property whose owners must comply with natural hazards disclosure requirements at time of property sale and 100 foot defensible space clearance. It is likely that the fire hazard severity zones will be used for updates to the safety element of general plans.

On October 30, 2015 Governor Brown issued an emergency declaration requiring public agencies to identify areas of tree mortality that hold the greatest potential to result in wildfire and/or falling trees and threaten people and property in these areas. Once identified, these areas will be prioritized for removal of dead and dying trees that present a threat to public safety. Tier Two high hazard zones are defined by watersheds (HUC 12, average 24,000 acres) that have significant tree mortality as well as significant community and natural resource assets. Work at the Tier Two level addresses the immediate threat of falling trees and fire risk, and also supports broader forest health and landscape level fire planning issues.This service represents the latest official release of HHZ. It will be updated annually when a new version is released. As of June 2019, it represents HighHazardZones19_1.

In 2012, the CPUC ordered the development of a statewide map that is designed specifically for the purpose of identifying areas where there is an increased risk for utility associated wildfires. The development of the CPUC -sponsored fire-threat map, herein "CPUC Fire-Threat Map," started in R.08-11-005 and continued in R.15-05-006.

A multistep process was used to develop the statewide CPUC Fire-Threat Map. The first step was to develop Fire Map 1 (FM 1), an agnostic map which depicts areas of California where there is an elevated hazard for the ignition and rapid spread of powerline fires due to strong winds, abundant dry vegetation, and other environmental conditions. These are the environmental conditions associated with the catastrophic powerline fires that burned 334 square miles of Southern California in October 2007. FM 1 was developed by CAL FIRE and adopted by the CPUC in Decision 16-05-036.

FM 1 served as the foundation for the development of the final CPUC Fire-Threat Map. The CPUC Fire-Threat Map delineates, in part, the boundaries of a new High Fire-Threat District (HFTD) where utility infrastructure and operations will be subject to stricter fire‑safety regulations. Importantly, the CPUC Fire-Threat Map (1) incorporates the fire hazards associated with historical powerline wildfires besides the October 2007 fires in Southern California (e.g., the Butte Fire that burned 71,000 acres in Amador and Calaveras Counties in September 2015), and (2) ranks fire-threat areas based on the risks that utility-associated wildfires pose to people and property.

Primary responsibility for the development of the CPUC Fire-Threat Map was delegated to a group of utility mapping experts known as the Peer Development Panel (PDP), with oversight from a team of independent experts known as the Independent Review Team (IRT). The members of the IRT were selected by CAL FIRE and CAL FIRE served as the Chair of the IRT. The development of CPUC Fire-Threat Map includes input from many stakeholders, including investor-owned and publicly owned electric utilities, communications infrastructure providers, public interest groups, and local public safety agencies.

The PDP served a draft statewide CPUC Fire-Threat Map on July 31, 2017, which was subsequently reviewed by the IRT. On October 2 and October 5, 2017, the PDP filed an Initial CPUC Fire-Threat Map that reflected the results of the IRT's review through September 25, 2017. The final IRT-approved CPUC Fire-Threat Map was filed on November 17, 2017. On November 21, 2017, SED filed on behalf of the IRT a summary report detailing the production of the CPUC Fire-Threat Map(referenced at the time as Fire Map 2). Interested parties were provided opportunity to submit alternate maps, written comments on the IRT-approved map and alternate maps (if any), and motions for Evidentiary Hearings. No motions for Evidentiary Hearings or alternate map proposals were received. As such, on January 19, 2018 the CPUC adopted, via Safety and Enforcement Division's (SED) disposition of a Tier 1 Advice Letter, the final CPUC Fire-Threat Map.

Additional information can be found here.

This polygon shapefile represents fire hazard severity zones in Fresno County, California.

This polygon shapefile represents fire hazard severity zones in Contra Costa County, California.

This polygon shapefile represents fire hazard severity zones in Orange County, California.

This polygon shapefile represents fire hazard severity zones in Yolo County, California.

The current dataset is appropriate for displaying the overall pattern of WUI development at the county level, and comparing counties in terms of development patterns. Until the dataset is refined through a field review and quality assurance process, it is not suited for WUI designations for individual houses or neighborhoods.The data can be downloaded as a file geodatabase here: GIS Mapping and Data Analytics | CAL FIREThree WUI classes are mapped:Wildland Urban Interface – dense housing adjacent to vegetation that can burn in a wildfire,Wildland Urban Intermix - housing development interspersed in an area dominated by wildland vegetation subject to wildfire, and Wildfire Influence Zone - wildfire susceptible vegetation up to 1.5 miles from Wildland Urban Interface or Wildland Urban Intermix. Wildland Urban Interface, Wildland Urban Intermix, and Wildfire Influence Zones. The model uses residential structure density and vegetative cover to define areas within the Fire Hazard Severity Zones. Primary Data Inputs:Fire Hazard Severity Zones (FHSZ_Assessment25_1)Housing Unit Density (HousingUnit_Density2020_DEN4)Secondary Data Inputs:(used to determine vegetation dominance)State Wildland Zones (FHSZ_State_Wildland_Zones_v17_1)Canopy Cover (CanopyCoverSALO2020)Fire Hazard Severity Zones: This source raster dataset represents Fire Management Analysis Zones as adopted officially on April 1, 2024 for State Responsibility Area (SRA) and as distributed to local governments in February and March of 2025 for Local Responsibility Areas (LRA). The source data for the LRA release also contains FHSZ coverage for Federal Responsibility Areas, but these data are used to fill out the state for assessment purposes only. Data sources: FHSZALL_v25_1 (SRA Approved and LRA Recommended) Statewide_v17_4 (Federal Responsibility Areas)Housing unit density classes for California derived from 30-m rasters extracted from Wildfire Risk to Communities: Spatial datasets of wildfire risk for populated areas in the United States and reprojected to California Teale Albers NAD87. DEN4 Description Less than 1 Housing Unit per 20 acres1 Housing Unit per 20 acres to 1 Housing Unit per 5 acresMore than 1 Housing Unit per 5 acres to 1 Housing Unit per acre More than 1 Housing Unit per acre After classifying, clusters of DEN4 values less than 80 cells (just under 18 acres) were nibbled to the nearest adjacent DEN4 class.State Wildland Zones and Canopy Cover: State Wildland Zones are used to determine the dominance of vegetation. Areas which would otherwise be classed as Wildland Urban Interface.area reclassed to Intermix if the vegetation cover is 50% or more. These canopy cover data are used in concert with SALO Canopy Cover to determine vegetation dominance in areas both within and outside of the the extent of the wildland zones.State Wildland Zones: State wildland zones are determined by the attribute flame class, which was derived as part of fire hazard modeling used in the determination of Fire Hazard Severity Zones and represent areas where wildland fire behavior can be assessed using common fire behavior tools. It is derived from fuel model attributes slope, and local fire weather conditions as processed through the NEXUS Fire Behavior platform, and reflects flame front characterization of intensity (flame length) that was then aggregated to fire environment polygons, averaged across the polygon area, and finally classified nominally according to quantile distributions with some threshold adjustments to reflect realistic class breaks for marginal areas of widely accepted hazard levels. All wildland zones are 50% or more vegetated.Canopy Cover: The horizontal cover fraction occupied by tree canopies. 2020 SALO Canopy cover data was downloaded for all California counties from here: https://forestobservatory.com/ on 5/17/2022 and mosaiced into one statewide dataset, reprojected from UTM 10 to Teale Albers NAD83 and resampled to 30m. Note: Vegetation dominance is determined as either FHSZ Wildland Zone 1-3 or SALO > 50% cover. A 3X3 cell circular focal mean is applied and areas with 0.5 or greater are considered at least 50% vegetated.-----------------------------------------------------------------These data are analyzed according to the following parameters:Interface:DEN4 Class 3 or 4 In Moderate, High, or Very High Fire Hazard Severity ZoneLess than 50% vegetation coverSpatially contiguous groups of 30m cells that are approximately 20 acres in size or largerIntermix:DEN4 Class 2 or 3In Moderate, High or Very High Fire Hazard Severity ZoneReclassed Interface:Interface cell groups less than 20 acresInterface that is 50% or more vegetated and in spatially contiguous groups of 30m cells that are at least 20 acres in size Intermix is spatially contiguous groups of 30m cells approximately 100 acres in size or largerInterface and Intermix are then combined. After combining, any cell group with fewer than 80 cells is classed to the value of its neighbor.Influence Zone:Up to 1.5 miles from Interface or IntermixIn Moderate, High, or Very High Fire Hazard Severity ZoneNot Interface or IntermixInterface, Intermix and Influence Zones are then combined. After combining, any cell group with fewer than 80 cells is classed to the value of its neighbor.A final step in the model addressed an inadvertent error invoked by the processing of potential interface conversion to Intermix for small fragments (<20 acres of Interface) and larger areas of Interface that were covered by a majority (>50%) vegetation within the areas otherwise defined as Interface because of meeting housing unit density and hazard requirements. When these lands were then subject to the final size minimum of 100 acres they then reverted to being potential buffer areas. This was remedied by selecting all lands that met the criteria of DEN4 values 3 and 4 (i.e.,all areas with housing density greater than 1 HU/ac) and reverting them to Interface designation. These previously eliminated but now reverted Intermix areas did not meet the 100 acre requirement and did not produce additional buffer zone influence areas from them. In most cases they are sufficiently embedded within Influence Zone buffers to be consistent with map objectives describing the land in terms of exposure and opportunity for community protection and risk mitigation.

This polygon shapefile represents fire hazard severity zones in Butte County, California.

This web map shows the current wildfires and fire danger zones within Canada. The layers used within this web map are Esri Canada's wildfire live feature services that are updated daily along with NRCan's current fire danger WMS. A description of each layer can be found below along with the link to their respective items on ArcGIS Online. Active Wildfires in Canada Reported active fire locations are updated daily as provided by fire management agencies (provinces, territories and Parks Canada). The fires data is managed through a national Data Integration Project (DIP) coordinated by the Canadian Interagency Forest Fire Centre (CIFFC) and Natural Resources Canada with participation from all partner agencies. The active fires data includes attributes for agency, fire name, latitude, longitude, start date, fire size (ha) and stage of control (fire status). Possible values for stage of control include: OC (Out of Control), BH (Being Held), UC (Under Control), EX (Out). Supplemental InformationThe national Data Integration Project (DIP) is coordinated by the Canadian Interagency Forest Fire Centre (CIFFC) and Natural Resources Canada with participation from all partner agencies. This initiative focuses on development and implementation of data standards and enabling the exchange and access of national fire data. More details are available in the CIFFC IM/IT Strategy, available at: https://ciffc.ca/publications/general-publications. Feux de végétation actifs au Canada Les positions rapportées des feux de végétation actifs sont mises à jour quotidiennement d'après les données fournies par les agences de gestion des feux (provinces, territoires et Parcs Canada). Les données sur les feux sont gérées dans le cadre d'un Projet d'intégration de données national coordonné par le Centre interservices des feux de forêt du Canada (CIFFC) et par Ressources naturelles Canada, avec la participation de tous les organismes partenaires. Les données sur les feux actifs comprennent les champs d'attributs des agences, le nom du feu, la latitude, la longitude, le début du feu, la taille du feu (ha) et le stade de contrôle (état du feu). Les valeurs possibles pour le stade de contrôle sont les suivantes : OC (out of control/hors de contrôle), BH (being held/contenu), UC (under control/maîtrisé) et EX (out/éteint). Renseignements complémentairesLe Projet d'intégration de données national est coordonné par le CIFFC et par Ressources naturelles Canada, avec la participation de tous les organismes partenaires. Cette initiative a pour but d'élaborer et de mettre en œuvre des normes de données, ainsi que de rendre possible l'accès aux données nationales sur les feux et l'échange de ces données. On trouvera plus de détails à ce sujet dans la Stratégie de GI/TI du CIFFC, à l'adresse suivante : https://ciffc.ca/publications/general-publications Active Wildfire Perimeters in CanadaThis dataset displays active wildfire perimeters derived from hotspots identified in satellite imagery provided by the Canadian Wildland Fire Information System (CWFIS) and Natural Resources Canada (NRCan) updated every 3 hours. || Ce jeu de données, mis à jour toutes les trois heures, affiche les périmètres de feux de forêt actifs dérivés des points chauds relevés dans l’imagerie satellite fournie par le Système canadien d’information sur les feux de végétation (SCIFV) et Ressources naturelles Canada (RNCan). Wildfire Smoke Forecast in Canada This layer displays forecasted wildfire smoke across Canada sourced from BlueSky Canada's FireSmoke Canada app, updated every 6 hours. The wildfire smoke layer consists of hourly concentrations of particulate matter 2.5 microns and smaller (PM2.5) in units of micrograms per meter cubed (µg/m3) observed at ground level from wildfires. It is an approximation of when and where wildfire smoke events may occur over the next two days. This layer is sourced from BlueSky Canada's FireSmoke Canada app. Current Fire Danger Fire Danger is a relative index of how easy it is to ignite vegetation, how difficult a fire may be to control, and how much damage a fire may do. Fire Danger is a reclassification of the CFFDRS fire weather index (FWI) which is a numeric rating of fire intensity. These general fire descriptions apply to most coniferous forests. The national fire danger maps show conditions as classified by the provincial and territorial fire management agencies. Choice and interpretation of classes may vary between provinces. For fuel-specific fire behavior, consult the Fire Behavior Prediction maps.• Low: Fires likely to be self-extinguishing and new ignitions unlikely. Any existing fires limited to smoldering in deep, drier layers.• Moderate: Creeping or gentle surface fires. Fires easily contained by ground crews with pumps and hand tools.• High: Moderate to vigorous surface fire with intermittent crown involvement. Challenging for ground crews to handle; heavy equipment (bulldozers, tanker trucks, aircraft) often required to contain fire.• Very High: High-intensity fire with partial to full crown involvement. Head fire conditions beyond the ability of ground crews; air attack with retardant required to effectively attack fire's head.• Extreme: Fast-spreading, high-intensity crown fire. Very difficult to control. Suppression actions limited to flanks, with only indirect actions possible against the fire's head.Forecasted weather data provided by Environment Canada. More information about forecasted weather is available at https://cwfis.cfs.nrcan.gc.ca/background/dsm/fwiMore information about the Canadian Forest Fire Weather Index (FWI) System is available at https://cwfis.cfs.nrcan.gc.ca/background/summary/fwiMaps are produced using Spatial Fire Management System and are updated multiple times per day. Maps updated daily, year-round.Supplemental InformationThe Canadian Forest Fire Danger Rating System (CFFDRS). is a national system for rating the risk of forest fires in Canada. Forest fire danger is a general term used to express a variety of factors in the fire environment, such as ease of ignition and difficulty of control. Fire danger rating systems produce qualitative and/or numeric indices of fire potential, which are used as guides in a wide variety of fire management activities. The CFFDRS has been under development since 1968. Currently, two subsystems–the Canadian Forest Fire Weather Index (FWI) System and the Canadian Forest Fire Behavior Prediction (FBP) System–are being used extensively in Canada and internationally.Risque d'incendie actuel Le risque d'incendie est un indice relatif indiquant le niveau de facilité pour allumer un incendie de végétation, le niveau de difficulté qu'un incendie peut demander pour être contrôlé ainsi que la quantité de dommages qu'un incendie peut causer.Ces descriptions générales des incendies s'appliquent à la plupart des forêts de conifères. Les cartes nationales sur le danger d'incendie illustrent les conditions telles qu'elles sont classées par les agences provinciales et territoriales de gestion des feux. Le choix et l'interprétation des classes peuvent varier entre les provinces. En ce qui a trait au comportement des incendies en regard du combustible spécifique, veuillez consulter les cartes de prédiction du comportement des incendies.• Faible: Incendie possiblement auto-extincteur; de nouveaux allumages sont invraisemblables. Tout incendie existant est limité à couver dans des couches profondes plus sèches.• Modéré: Incendie de surface rampant modéré. Il est facilement circonscrit par les équipes au sol munies de pompes et d'outils manuels.• Élevé: Incendie de surface modéré à vigoureux avec implication intermittente des cimes. Pose des défis aux équipes chargées de le combattre sur le terrain; les équipements lourds (bouteurs, camions-citernes à eau et avions) sont souvent requis pour contenir l'incendie.• Très élevé: Incendie de forte intensité avec implication partielle ou complète des cimes. Les conditions au front de l'incendie sont au-delà de la capacité des équipes sur le terrain à y faire face; les attaques aériennes avec largage de produits ignifugeants sont requises pour combattre effectivement le front de l'incendie.• Extrême: Feu de cimes à forte intensité et à propagation rapide. Très difficile à contrôler. Les actions de suppression sont limitées aux flancs alors que seules des actions indirectes sont possibles au front de l'incendie.Prévisions météorologiques fournies par Environnement Canada. Pour de plus amples renseignements sur les prévisions, consultez la section Renseignements généraux.De plus amples informations sur la Méthode canadienne de l'indice Forêt-Météo (IFM) sont disponibles à la rubrique Renseignements généraux.Les cartes sont produites à l'aide du Système de gestion spatiale des feux de forêt et sont mises à jour plusieurs fois par jour.Les cartes sont mises à jour quotidiennement, tout au long de l'année l'année.Renseignements complémentairesLa Méthode canadienne d'évaluation des dangers d'incendie de forêt (MCEDIF) est une méthode nationale pour classer le risque d'incendie de forêt au Canada.Le danger d'incendie de forêt est un terme général employé pour exprimer une diversité de facteurs dans les conditions de brûlage tels que la facilité d'allumage et la difficulté de contrôle. Les méthodes d'évaluation du danger d'incendie génèrent des indices qualitatifs ou numériques du potentiel d'incendie qui sont utilisés comme guides dans une grande variété d'activités de gestion des incendies de forêt. La MCEDIF est en cours d'élaboration depuis 1968. En ce moment, deux sous-systèmes – la Méthode canadienne de l'indice forêt météo (IFM) et la Méthode canadienne de prévision du comportement des incendies de forêt (PCI) – sont couramment utilisés au Canada et sur

Throughout the state, CAL FIRE has 21 operational units that are designed to address fire suppression over a certain geographic area. Each unit operates within their local jurisdiction and strives to fulfill the department's mission whether it be responding to all-risk emergencies, participating in fire safety education and educating homeowners on how to keep their property fire safe. In addition, CAL FIRE provides funding to six 'Contract Counties' (Kern, Los Angeles, Marin, Orange, Santa Barbara and Ventura) for fire protection services, including wages of suppression crews, lookouts, maintenance of fire fighting facilities, fire prevention assistants, pre-fire management positions, dispatch, special repairs, and administrative services. The Department's budget also provides for infrastructure improvements, and expanded fire fighting needs when fires grow beyond initial attack. Contract Counties are responsible for providing initial response to fires on SRA. When a wildland fire escapes this initial attack, CAL FIRE responds with fire fighting resources to assist the county.This service represents the latest official version of the CAL FIRE Administrative Units dataset, and is updated whenever a new version is released. As of May 2023, it represents cdfadmin23_1.

The foundation of quantitative wildfire hazard or risk assessment is a current-condition fuelscape (i.e., fuel and terrain layers), ideally updated to account for recent disturbances and calibrated to reflect the fire behavior potential observed in recent historical wildfire events. This data publication provides the fuelscape generated for a wildfire risk assessment focused on the sagebrush biome of the western United States (US). The data depict ca. 2020 fuel conditions, after customization, to better reflect expected fire behavior in sagebrush ecosystems, including influences from exotic annual grass (e.g., cheatgrass) invasion and conifer (e.g., pinyon, juniper) encroachment. These data are presented as used for biome-wide geospatial fire modeling at a 270-meter resolution. The work was conducted using simulation units called “pyromes,” which represent areas of relatively homogenous contemporary fire regimes. The sagebrush biome is represented by 31 pyromes, covering about 450 million acres in total area. Fuelscapes for the 31 pyromes are included in this data product as separate multiband GeoTIFFs. The bands of each GeoTIFF store eight layers of data that describe terrain (aspect, elevation, slope), tree canopy (cover, height, base height, bulk density), and surface fuel (FBFM40). These data form the Landscape (LCP) file commonly used by US wildland fire behavior modeling systems (e.g., FlamMap, FSPro, FSim). Each fuelscape dataset includes a 30-kilometer buffer to avoid truncating the simulated fires at pyrome boundaries. A shapefile and geopackage containing the boundaries and size of each pyrome are also included.In the western United States, hundreds of thousands of acres of highly imperiled sagebrush ecosystems are lost or degraded each year as a result of altered wildfire regimes. In response to these wildfire threats, extensive fuel treatment investments have been proposed throughout the region. Regional-scale assessment of wildfire risk offers a consistent means of evaluating threats to valued resources and assets, thereby facilitating the most cost-effective investments in management activities that can mitigate those risks. We used a large-fire simulation system (FSim) to estimate the probabilistic components of wildfire risk across the sagebrush biome, which includes portions of 13 western states. This publication includes the customized fuelscape data used for that fire-modeling work.

A Fire Disturbance Area represents the mapped exterior perimeter of a forest fire. Mapping is derived from a variety of sources, such as GPS points and digitized paper maps. Prior to 1998, only fires greater than 200 hectares were mapped. Since 1998, fires greater than 40 hectares have been mapped. If adequate mapping exists for fires less than 40 hectares in size, they will be included in this data class. The Forest Fire Info Map shows active fires, current fire danger and restricted fire zones in place due to high fire danger.

This polygon shapefile represents fire hazard severity zones in Plumas County, California.

This polygon shapefile represents fire hazard severity zones in Marin County, California.

Public Resources Code 4201-4204 directs the California Department of Forestry and Fire Protection (CAL FIRE) to map fire hazard within State Responsibility Areas (SRA) 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. These zones, referred to as Fire Hazard Severity Zones (FHSZ), classify a wildland zone as Moderate, High, or Very High fire hazard based on the average hazard across the area included in the zone.