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PMS 437

CFFDRS System Overview

  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).

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

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.

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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.

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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.

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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.

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Wind Observations

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

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Open Windspeed Chart: Use only 10m for effective windspeed

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.

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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).

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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)

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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.

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

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NWCG Latest Announcements

Updated NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515

Date: May 10, 2024
Contact: IFUASS Qualification and Curriculum Board (IFUASS) 

The 2024 revision of the NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515 is now available. PMS 515 standardizes the processes and procedures for interagency use of Unmanned Aircraft Systems (UAS), including pilot inspections and approvals. This publication is now available as a PDF for easy use offline.

References:

NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515

Memorandum 24-003: Removal of Type 1 Command and General Staff (C&G) Incident Position Qualification Pathways

Date: May 10, 2024
Contact: Aitor Bidaburu 

The purpose of this memorandum is to provide NWCG direction for removal of the Type 1 Command and General Staff (C&G) incident position qualification pathways to transition to Complex Incident Management (CIM). Responders may continue to utilize available NWCG pathways to attain Type 1 C&G qualifications until December 31, 2024.

References:

Memorandum 24-003

CIM Story Map

2024 Professional Reading Program

Date: April 26, 2024
Contact: Wildland Fire Leadership Development Program (WFLDP) 

The Wildland Fire Leadership Development Program is announcing the 2024 Professional Reading list! The intent of the Professional Reading Program is to promote the reading and discussion of these books throughout the year. Discussion guides are provided and the corresponding Wildland Fire Leadership Levels have been identified.

The five books chosen for this year are: Young Men and Fire by Norman Maclean, The Wisdom of the Bullfrog by William H. McRaven, The Art of Clear Thinking by Hasard Lee, Emotional Agility by Susan David, and Writing to Persuade by Trish Hall.

References:

Professional Reading Program

Wildland Fire Leadership Levels

NWCG Training Catalog now on Wildland Fire Learning Portal

Date: April 25, 2023
Contact: NWCG Training  

The National Wildfire Coordinating Group (NWCG) has migrated the training catalog from the NWCG website to the Wildland Fire Learning Portal (WFLP) as part of our ongoing efforts to streamline processes and improve efficiency. To facilitate this transition, the training catalog remains available on www.nwcg.gov through April 2024.

Starting May 2024, the training catalog will no longer be accessible on www.nwcg.gov. However, you can still access the complete training catalog by logging in as a guest to the WFLP.

References:

Wildland Fire Learning Portal