Search Fire Behavior Field Reference Guide, PMS 437

Text (indexed):
  1. Other Fire Danger Resources
  2. Drought Assessment Resources
  3. Fire Danger References
  4. Publications

Other Fire Danger Resources

Alaska Fire Weather Index (FWI)

Florida Wildland Fire Danger Index (FDI)

Georgia Forestry Commission Fire Weather System

Great Lakes Fire Weather Index (FWI)

Maine Wildfire Danger Report

Michigan DNR Wildland Fire Application

Minnesota DNR Wildfire Information Center

New York State Fire Danger Map

North Carolina Fire Weather Intelligence Portal

OK-Fire, Oklahoma Mesonet

Santa Ana Wildfire Threat Index

Drought Assessment Resources

Western Water Assessment (NOAA Regional Integrated Sciences and Assessments)

The Drought Monitor (National Drought Mitigation Center)

National Integrated Drought Information System (National Centers for Environmental Information)

National Drought Mitigation Center (University of Nebraska – Lincoln)

Fire Danger References

Online Resources

Publications

Andrews, P. L.; Bradshaw, L. S.; Bunnell, D.; and Curcio G., Fire Danger Rating PocketCard for Firefighter Safety, Symposium on Fire and Forest Meteorology, 1997.

Bradshaw, L. S.; Deeming, J. E.; Burgan, R. E.; and Cohen, J. D., The 1978 National Fire-Danger Rating System: technical documentation, U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station; 1984. 

Burgan, R. E., 1988 Revisions to the 1978 National Fire-Danger Rating System, USDA Forest Service, Southeastern Forest Experiment Station, Research Paper, 1988.

Deeming, J. E.; Burgan, R. E.; and Cohen, J. D., The National Fire-Danger Rating System – 1978USDA Forest Service, Intermountain Forest and Range Experiment Station, 1978.

Fosberg, M. A., and Deeming, J. E., Derivation of the 1 and 10-hour timelag fuel moisture calculations for fire-danger rating, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, 1971.

Jolly, W.M.; Nemani, R.; and Running, S.W., A generalized, bioclimatic index to predict foliar phenology in response to climate, Global Change Biology, 2005.

Remote Sensing/Fire Weather Support Unit, Interagency Wildland Fire Weather Station Standards and Guidelines, PMS 426-3, National Wildfire Coordinating Group, 2014.

Nelson R.M., Jr., Prediction of diurnal change in 10-h fuel stick moisture contentCanadian Journal of Forest Research, 2000.

Schlobohm, P., and Brain, J., Gaining an Understanding of the National Fire Danger Rating System, PMS 932, National Wildfire Coordinating Group, 2002.

Text (indexed):
  1. Introduction
  2. Use of English Units
  3. Wind Observations
  4. Fire Intensity Measures

Introduction

The Canadian Forest Fire Danger Rating System, as shown in these flow charts, is a comprehensive system of tools designed to evaluate environmental factors that influence the ignition, spread, and behavior of wildland fire. Additional detail about the system and its subsystems can be learned from an introductory certificate online course and direct access to the YouTube videos that support it:

CFFDRS Components

The system had its origins from early efforts dating to the 1920s and the development of the Tracer Index, a forerunner of the Fine Fuel Moisture Code (FFMC).

Components of the Canadian Forest Fire Danger Rating System. This diagram outlines the major components, there interrelations, and how they impact fire management considerations.

Fire Weather Index (FWI) System Process Flow Chart

The FWI system was developed and introduced across Canada in 1970. Due to its simplicity in terms of data required and outputs produced, it is used both globally and within many regions around the world.

The Fire Weather Index System. This process flow chart outlines the system inputs, as well as the array of output codes and indices.

Fire Behavior Prediction (FBP) System Process Flow Chart

The FBP system tools were released in interim form in 1984, with a more formal introduction in 1992, and revisions in 2008.

The Fire Behavior Prediction System. This process flow chart outlines the system inputs, as well as the array of primary fire behavior and secondary fire growth characteristics.

Additional systems for fuel moisture (e.g. hourly FFMC and Grass Fuel Moisture) and ignition have followed.

There are several important distinctions for NFDRS and NFBPS users.

Use of English Units

All the CFFDRS tools and references produced by the Canadian and Provincial governments, as well as applications produced internationally, use the metric system for all measured values. For the most part, measures referenced here are in English units to facilitate utility and use in the United States.

Wind Observations

This table provides a quick reference to aid conversion between 10m, 20ft, unsheltered Eye Level (EL Op) observations, and Forecast/Airport winds. 

Conversion Chart for Open Windspeed. This chart estimates the relative windspeed estimates, based on sensor height (10m, 20ft, and eye level) and the effect of surrounding terrain at sensor location (Airport vs Forestry/Fire RAWS location).

CFFDRS weather observations, provided to the system for both FWI and FBP calculations, generally conform to familiar fire weather standards. These standards can be reviewed in the weather guide table referenced above. However, wind observation standards conform to the international 10m height as opposed to the NFDRS 20-foot height standard.

This depiction highlights the difference in height standard among fixed and handheld wind sensors used in fire management applications.

(Andrews, 2012)

CFFDRS models and tools do not expressly apply relationships between the standard 10m wind measurements and others that U.S. users may be familiar with. Both 20-foot and eye level winds are commonly referenced and reported from U.S. RAWS observing locations and from the fireline.

Further, wind speeds reported from Airport ASOS (Automated Surface Observing System) and provided in National Weather Service forecasts generally report higher wind speed, where surrounding terrain is flat with little variation in vegetation height or structural interference, and is highly correlated with forecast wind speed provided in the National Digital Forecast Database (Lawson and Armitage, 2008).

Surrounding terrain and surface characteristics affect the windspeed measured by sensors. Compares the speeds measured at generally flat/smooth surfaces around airport sensors, more variable and rougher terrain found in forest RAWS settings, and the highly modified results obtained in urban settings.

(Lawson & Armitage, 2008)

Fire Intensity Measures

A major adaptation in U.S. tools and references, with uncertain validity, is the use of flame length for fire intensity outputs in the Fire Behavior Tables. FBP outputs (kW/m) were converted to BTU/ft/sec using standard conversions and then to flame length using the formula:

Flame Length = .45*"BTU/Ft/Sec"^.46

This table identifies the CFFBP Fire Intensity thresholds in kW/m and the corresponding values in English units (BTU/ft/sec) and flame length in feet. These thresholds are consistent with commonly held flame length thresholds for fire safety interpretations in the U.S. system.

The Fire Intensity Class Conversion Table shows the relationship among English and metric representations of fireline intensity at key threshold levels.

 

Text (indexed):
  1. Introduction
  2. Fire Weather Index – NFDRS Crosswalk
  3. FWI Fuel Moisture Codes
  4. FWI Fire Behavior Indices
  5. Grass Fuel Moisture (GFM)
  6. Other Considerations

Introduction

Analogous in concept to the National Fire Danger Rating System (NFDRS), the FWI System depends solely on weather readings. Resulting fuel moisture codes and fire behavior indices are based on a single standard fuel type that can be described as a generalized pine forest, most nearly jack pine and lodgepole pine.

The Fire Weather Index System calls for weather observations to be collected from a standard observation site and time. Location standards can be found in the, Weather Guide for the Canadian Forest Fire Danger Rating System (Lawson and Armitage, 2008). The system calls for observations to be taken at solar noon, when the sun is at its peak directly overhead.

Reference tools and current conditions are available to US users through:

FWI Process Flow Chart

 The Fire Weather Index System. This process flow chart outlines the system inputs, as well as the system array of output codes and indices.

Fire Weather Index – NFDRS Crosswalk

This table provides the crosswalk between FWI weather inputs, fuel moisture codes, and fire behavior indices with their NFDRS counterparts.

Comparison of Fire Weather Index (FWI) and National Fire Danger Rating (NFDRS) Systems. Establishes crosswalks of comparable elements of inputs and system outputs.

FWI Fuel Moisture Codes

There are 3 fuel moisture categories, or codes, in the FWI system, compared to 7 found in NFDRS. These are generally represented as unitless codes instead of fuel moisture content (represented as a % of dry weight). They can be converted to moisture content, and in fact, are converted each day as part of the daily or hourly calculations.

The Fine Fuel Moisture Code (FFMC) represents fuel moisture of forest litter fuels under the shade of a forest canopy. It is intended to represent moisture conditions for shaded litter fuels, the equivalent of 16-hour timelag. It ranges from 0-101. Subtracting the FFMC value from 100 can provide an estimate for the equivalent (approximately 10h) fuel moisture content, most accurate when FFMC values are roughly above 80.

The Duff Moisture Code (DMC) represents fuel moisture of decomposed organic material underneath the litter. System designers suggest that it is represents moisture conditions for the equivalent of 15-day (or 360 hr) timelag fuels. It is unitless and open ended. It may provide insight to live fuel moisture stress.

The Drought Code (DC), much like the Keetch-Byrum Drought Index, represents drying deep into the soil. It approximates moisture conditions for the equivalent of 53-day (1272 hour) timelag fuels. It is unitless, with a maximum value of 1000. Extreme drought conditions have produced DC values near 800.

This example plot of all three moisture codes through a fire season demonstrates how fuel moisture codes rise as fuels dry out, and falls with precipitation and (primarily with FFMC) with moderating weather.

Example plot of fuel moisture trends from 2015 season at the Hogatza RAWS in Alaska. It shows that FWI system fuel moisture codes rise as fuels dry and fall as they are wetted by precipitation.

In this way, these fuel moisture codes can more easily provide visual comparisons with the associated fire behavior indices. Among them, the DMC and DC are effectively open ended codes with little chance environmental conditions will produce maximum values.

The FFMC, representing moisture conditions in shaded forest litter, is analogous to 10-hr fuel moisture estimates. This table suggests the conversion for both shaded (10h-Sh) and unshaded (10h-Unsh) fuel bed conditions:

FWI Fire Behavior Indices

There are 3 fire behavior indices in the FWI system:

  • The Initial Spread Index (ISI) is analogous to the NFDRS Spread Component (SC). It integrates fuel moisture for fine dead fuels and surface windspeed to estimate a spread potential. ISI is a key input for fire behavior predictions in the FBP system. It is unitless and open ended.
  • The Buildup Index (BUI) is analogous to the NFDRS Energy Release Component (ERC). It combines the current DMC and DC to produce an estimate of potential heat release in heavier fuels. It is unitless and open ended. In Alaska and the Lake States, it is the primary indicator of season severity during the growing season.
  • The Fire Weather Index (FWI) integrates current ISI and BUI to produce a unitless index of general fire intensity potential. It is analogous to NFDRS Burning Index. With dry fuel conditions, it is a key indicator of extreme fire behavior potential. Again, unitless and open ended.

As shown in this graph, the FWI integrates the influences of spread (ISI) and fuel flammability (BUI) to produce a unitless index of potential fire intensity and prospect for extreme fire behavior.

Example plot of fire behavior indices from 2015 season at the Hogatza RAWS in Alaska. It shows that FWI system of indices represent day to day changes in spread (Initial Spread Index), fuel consumption (Buildup Index), and fire intensity (Fire Weather Index).

Grass Fuel Moisture (GFM)

The GFM is a fourth fuel moisture category for grass fuel moisture specifically (Wotton, 2009). It is not part of the daily FWI system. Research in Ontario (Kidnie et.al, 2010) quantified the fuel moisture trends for grass fuels and established a grass fuel moisture model that is produced only with hourly data. Its corresponding Grass Fuel Moisture Code (GFMC), along with the FFMC, provides hourly estimates to represent diurnal and event based changes in fine fuel moisture as they occur.

Grass Fuel Moisture (GFM) Estimation Table. Though not part of the daily FWI system, grass fuel moisture is an important characteristic of diurnal changes to flammability in grass systems.

Other Considerations

Diurnal Variations

There is an hourly version of the Fine Fuel Moisture Code that reflects variability influenced by temperature and humidity changes throughout the day and night. Using the corresponding, locally observed windspeed, updated values for Initial Spread Index and Fire Weather Index may also be produced.

Seasonal Start-up and Resumption after Interruption in Observations

Daily records are generally started as soon as there is measurable fire danger in the spring. Where winter snow cover is continuous, this is defined as the third day after snow has left the area to which the fire danger rating applies. Default seasonal start-up values are 85 for FFMC, 6 for DMC, and 15 for DC.

If daily observations are interrupted during the season and missing observations cannot be estimated, fuel moisture codes must be estimated for the last day of missing observations and used as “yesterday” fuel moisture codes for the newly resumed weather observation.

Text (indexed):
  1. Introduction
  2. Weather Inputs
  3. FBP Fuel Types
  4. Example Fire Behavior Lookup Table

Introduction

The CFFDRS FBP system is not integrated into the U.S. fire behavior analysis tools, e.g.,  BehavePlus, FARSITE, FlamMap, WFDSS, or IFTDSS. Tools are available to U.S. users via the following:

This flowchart highlights the basic inputs and outputs for the FBP system, demonstrating many similarities to the US tools provided to support fire behavior prediction.

 The Fire Behavior Prediction System. This process flow chart outlines the system inputs, as well as the array of primary fire behavior and secondary fire growth characteristics.

However, there are significant differences. Most important are the way that weather (fuel moisture and wind) and fuel (fuel types) are applied.

Weather Inputs

The ISI and BUI, drawn from the daily FWI system and adjusted for local conditions, are used directly as wind and fuel moisture inputs in fire behavior calculations. This facilitates the use of RAWS observations in fire behavior estimation.

FBP Fuel Types

Designed specifically for use in predicting the full range of fire behavior in northern forest ecosystems, there are 18 fuel types among five fuel groups. The classification recognizes coarse vegetative cover and structure types. Each CFFBP Fuel Type integrates the surface and canopy fuel characteristics, providing for evaluation of crown fire initiation and propagation without additional canopy characterizations.

An Excel workbook for comparing fuel types is available for download here.

Conifer Fuel Types

These fuel types represent the most important fire potential throughout the boreal forest. C-2 (spruce) and C-4 (pine) represent extreme potential with active crown fire anticipated under most conditions. C-3, C-5, and C-7 represent more moderate potential with taller trees and higher surface to canopy gaps.

Conifer fuel type characteristics chart. Descriptions to aid in identification and graph of relative spread rates.

Grass Fuel Types

These two grass fuel types are intended to differentiate between spring grass fuel beds (O-1a after snowmelt and late summer cured grass fuelbeds (O-1b). Their use requires characterization of the curing level in the grasses. They can be used for flammable grass/shrub fuelbeds, though generally require lower curing levels to properly slow spread rates.

Grass/Openland fuel type characteristics chart. Descriptions to aid in identification and graphs of relative spread rates.

Mixed Wood Fuel Types

Common to the Boreal Forest, these fuel types represent areas where varying combinations of conifers and hardwoods can support a range of crown fire potential ranging from torching trees to active crown fire. Use of these fuel types usually require assumption of the conifer percentage in the canopy fuels.

Mixedwood fuel type characteristics chart. Descriptions to aid in identification and graphs of relative spread rates.

Deciduous Fuel Types

These fuel types were calibrated to largely pure stands of Trembling Aspen and/or Paper Birch. They may over-estimate potential in northern hardwood stand of the eastern U.S. and underestimate potential in oak dominated central hardwoods of the eastern and central U.S.

Deciduous fuel type characteristics chart. Descriptions to aid in identification and graph of relative spread rates.

Slash Fuel Types

Calibrated to post-logging fuelbeds with substantial fuel loads, they may or may not effectively represent blowdown areas.

Slash/Blowdown fuel type characteristics chart. Descriptions to aid in identification and graph of relative spread rates.

Example Fire Behavior Lookup Table

FBP Lookup tables can be found in the Field Guides (AK, MI, MN) that can be downloaded at the links below or at the top of the section. This example shows that spread rates, flame lengths, and fire type can be determined once the user has identified the fuel type, the ISI, and the BU( or grass curing for open types.

Fire Behavior Lookup Tables aid system user in the estimation of spread rates, flame length/fire intensity, and the type of fire anticipated.

Text (indexed):

Fire Behavior Observations

This standardized fire behavior observation tool integrates the classification applied in fire danger and fire behavior characteristics charts, visual cues to significant classes of fire behavior, and appropriate terminology.

CFFDRS Fire Observation/Description chart. This guide identifies key terms for describing fire behavior and provides reference imagery and descriptive detail to aid observation reports.

Text (indexed):
  1. Online Resources
  2. User Guides
  3. Other References

Online Resources

Alaska CFFDRS - access to Alaska specific FWI displays (maps, tables, graphs) and database downloads along with FBP calculator.

Great Lakes CFFDRS - access to Great Lakes specific FWI displays (maps, tables, graphs) and database downloads along with FBP Calculator. NFDRS displays are also available.

FRAMES Online CFFDRS Course and YouTube Video Presentations provide background explanations of the FWI and FBP systems for US users.

REDapp - free, stand-alone FBP software (metric units).

Prometheus - growth simulation.

User Guides

These localized field guides provide desk and fireline references for estimating FWI codes and indices and conducting a fire behavior assessment using the FBP system.

Other References

Andrews, Patricia L., Modeling wind adjustment factor and midflame wind speed for Rothermel’s surface fire spread model. Gen. Tech. Rep. RMRS-GTR-266. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 2012.

Tables for the Canadian Forest Fire Weather Index System, Canadian Forestry Service, Forest Technical Report, 1984.

De Groot, W.J., Examples of Fuel Types in the Canadian Forest Fire Behavior Prediction (FBP) System, Forestry Canada, Poster. Forestry Canada Fire Danger Group. 1992.

Development and structure of the Canadian Forest Fire Behavior Prediction System, Science and Sustainable Development Directorate. 

Hirsch, K.G., Canadian Forest Fire Behavior Prediction (FBP) System User's GuideNatural Resources Canada, Canadian Forest Service, Northern Forestry Centre Special Report 7, 1996.

Kidnie, S.M., Wotton, M.M., Droog, W.N., Field Guide for Predicting Fire Behaviour in Ontario’s Tallgrass Prairie, 2010.

Lawson, B.D.; Armitage, O.B., Weather guide for the Canadian Forest Fire Danger Rating System, Nat. Resour. Can., Can. For. Serv., North. For. Cent., 2008.

Tymstra, C.; Bryce, R.W.; Wotton, B.M.; Taylor, S.W.; Armitage, O.B., Development and structure of Prometheus: the Canadian Wildland Fire Growth Simulation Model, Nat. Resour. Can., Can. For. Serv., North. For. Cent., 2010.

Taylor, S.W., Pike, R.G., Alexander, M.E., Field Guide to the Canadian Forest Fire Behavior Prediction (FBP) System, Canadian Forest Service, Northern Forestry Centre, Special Report, 1997.

Van Wagner, C.E., Development and structure of the Canadian Forest Fire Weather Index System, Canadian Forest Service, Ottawa, Ont. Forest Technical Report 35, 1987.

Wotton, B.M.; Alexander, M.E.; Taylor, S.W., Updates and Revisions to the 1992 Canadian Forest Fire Behavior Prediction SystemNatural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre,  2009.

Wotton B.M., A grass moisture model for the Canadian Forest Fire Danger Rating System, Fire and Forest Meteorology Symposium, 2009.

Text (indexed):
  1. Sources of Digital Weather and Fire Records
  2. Creating a FireFamily Plus Database for Weather Analysis
  3. Critique and Edit in FireFamily Plus

Sources of Digital Weather and Fire Records

FAMWEB Fire and Weather Data

Provides access to all archived daily fire weather records for NFDRS stations in the United States, both manual and automated. It also is the source of fire occurrence data for all federal agencies and some state agencies. These files are formatted for easy import into FireFamily Plus. Updated annually.

FAMWEB Fire/Weather Data Extract

Provides user requested access to archived and current weather records from NFDRS stations in the United States. Hourly records are stored for the most recent years and all daily records archived in the Weather Information Management System (WIMS) are available. Fire occurrence records are available as well. File formats are compatible with FireFamily Plus import. Updated daily.

Climate, Ecosystem and Fire Applications (CEFA)

Provides hourly data as well. Enter a WIMS ID into this application to quickly export all hourly records dating back to when the solar radiation sensor was installed on that station. Updated monthly.

Western Region Climate Center

Provides an archive to all Satellite (GOES) enabled RAWS stations. It is the most complete archive of hourly observations for the RAWS network. The interface provides many display alternatives (wind rose, summary tables, frequency distributions, and station metadata). The data lister provides for data download of archived data with a user password. Updated hourly.

Mesowest

Provides access to hourly data for a wide variety of weather stations across the United States.  Outputs include map displays, tables, and graphs.  For users that want to download quantities of data, consider Mesonet API where both ad-hoc queries and programmable requests can be formatted. Updated hourly.

Iowa Environmental Mesonet (IEM)

Provides a range of products for a variety of networks around the world.

Local Online Resources

These and other resources should be considered and may be found by asking local managers and experts.  Some examples include:

Creating a FireFamily Plus Database for Weather Analysis

Consider these steps when creating a FireFamily Plus database for your analysis area.  You will want hourly data if you intend to use NFDRS 2016 fuel models, components, and indices.  And this order will ensure that you get data with updated snowflag inputs. 

  1. Download historic hourly data in FW13 file format from 2018 forward from the National Fire and Aviation Management (FAMWEB) website.  Select Weather from Fire/Weather Data Extract to access download links. You will need the WIMS station ID number to request the download. This information will be current as managed by local dispatch office procedures.
  2. Download historic hourly weather data in FW13 file format from the CEFA site. This data is current through 2017. You will need the WIMS station ID number to request the download.
  3. Station catalog files can be found on the National Fire and Aviation Management (FAMWEB) website. Select Weather from Fire/Weather Data Extract to access download links.  You will need the WIMS station ID number to request the download.
  4. Create new FFP database or open an existing one as needed.
  5. Import station catalog into the database.  It should update the record that may be there.
  6. Import FAMWEB historic weather record into the database for stations of interest first.
  7. Import CEFA historic weather record into the database for stations of interest. Do not overwrite data from step 6.
  8. Review the station catalog and the weather record span and continuity.

Critique and Edit in FireFamily Plus

FireFamily Plus is fire and weather analysis available at the Fire, Fuel, Smoke Science Program and can be used effectively to review and edit archived weather records obtained from the sites listed above. The following steps can help evaluate the weather record for time span, accuracy, and completeness, once the records are imported:

  1. Evaluate the Active Working Set for the archive to determine if the record has a sufficient time span (15+ years) for climatological analyses.
  2. Evaluate the completeness of the record by evaluating the data count for the archive. Does the station collect records year round? If not, what period of the year appears to have a relatively complete record?
  3. Evaluate individual data elements to determine the archive’s accuracy. Look for outliers among the basic data observations (temp, RH, wind speed, precipitation, max and min values) by sorting records in ascending and descending order to locate erroneous values.
  4. Evaluate data elements and calculated components and indices by displaying climatology graphs (max, min) and individual years to find erroneous trends and outliers.
  5. Evaluate the wind rose to determine whether the station’s wind observations (speeds and directions) are representative of the fire situation being analyzed.

It may be appropriate to edit the records, which can be done in the View Observations table. Before changing archived observation, the record in question should be compared to those of surrounding stations. Any changes made, should be documented for the local fire management agency.