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Surface Fire Behavior Worksheet

Table of Contents for This Page

  1. Available Tools and Resources
  2. Required Surface Model Inputs
  3. Surface Model Outputs
  4. Acceleration Effect on Rate of Spread

This comprehensive worksheet can be used with the surface fire behavior lookup tables, the Nomograms and Nomographs, as well as BehavePlus, and runs if you want a paper copy.

Consider using this as your briefing documentation by including a weather forecast narrative, your thoughts about recent fire activity, your sense of how accurate the predictions seem, and when you expect changes through the burn period.

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Worksheet for recording information collected and estimates produced when estimating surface fire behavior.

Available Tools and Resources

This section describes how to estimate expected surface fire behavior and provides several references tools used in the process:

  1. A Worksheet (above) designed to document a complete assessment for surface fire behavior and growth using either the lookup tables or the nomographs.
  2. EWS Tables for estimating Effective Windspeed from Slope and Midflame Windspeed. The Effective Windspeeds that result from these tables assumes that wind is blowing ± 30° from upslope. For other situations, manual vectoring using the EWS Table would be necessary.
  3. Surface Fire Behavior Lookup Tables for making estimates of surface fire spread and flame length. Note these assumptions:
    • 10-hr and 100-hr moisture values of 6% and 8% are used in the lookup tables.
    • The *20ft/FCST wind line is provided as a convenience, but only works with stated Wind Adjustment Factor (WAF) & no slope adjustments.
    • Backing & flanking columns are only rough estimates based on ½ and 1 mph windspeeds. Use the Flanking and Backing Fire Behavior Nomograph , or BehavePlus for more precise estimates.
  4. Instructions for Surface Fire Behavior Nomographs and Nomograms.
  5. Flanking and Backing Fire Behavior Nomograph for estimating rate of spread and flame length where fire is spreading more slowly on the flanks and at the back of the fire perimeter.

These tools can help you make expected surface fire behavior estimates. Consider the following:

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Required Surface Model Inputs

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Surface Model Outputs

  • Rate of Spread is useful in fireline tactical applications; identifying what is at risk in the burn period, escape route limitations.
  • Flame Length/Fireline Intensity is used generally in determining what tactics make sense during the peak burn period, interpreting safety zone concerns, and suggesting spotting potential.
  • Heat per Unit Area is available from nomograms and BehavePlus. Like the Energy Release Component, it may be helpful in suggesting burn duration and fire effects.

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Acceleration Effect on Rate of Spread

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Fire Spread Acceleration. Fire spread accelerates over a period of time after initiation. The period of time varies based on the fuelbed.

Fire acceleration is defined as the rate of increase in fire spread rate. It affects the amount of time required for a fire spread rate to achieve the theoretical steady state spread rate given 1) its existing spread rate, and 2) constant environmental conditions.

Because initiating fires can take 20 minutes to over an hour to reach a steady spread rate, fire behavior and fire growth can be significantly reduced in the first burn period, and when beginning to spread in subsequent periods.

At this time, fire acceleration is implemented only in FARSITE, using the model developed for the Canadian Forest Fire Behavior Prediction System (Alexander et. al. 1992).

It is active by default, but can be turned off as a model input.

As implemented, inputs are segregated by type of Ignition (point vs. line source) and potentially by fuel type (grass, shrub, timber, slash, a default, or by fuel model). Grass fuels are expected to have more rapid acceleration rates (shorter time to reach equilibrium) than fuel types with larger woody material (slash, etc.).

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NWCG Latest Announcements

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

Date: April 23, 2025
Questions?  Please contact:
Interagency Fire Unmanned Aircraft Systems Subcommittee

The NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515 standardizes processes and procedures for the interagency use of Unmanned Aircraft Systems (UAS), including pilot inspections and approvals. This updated publication provides the aviation community with standards to ensure UAS are used safely, effectively, and efficiently in support of fire management goals and objectives.

References:

NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515

NWCG National Interagency Aviation Committee

ETC Bulletin 25-001: Retrofitted Hot/Cold Beverage Kits - 2025 Field Season

Date: April 16, 2025
Questions?  Please contact:
Equipment Technology Committee

Due to spout failures and the associated risk of burn injuries, manufacturers have retrofitted the Hot/Cold Beverage Kits using a heat-shrinking band to secure the black spout at the insertion site. The updated kits feature a fluorescent label on each full kit assembly for easy identification. Catering units are encouraged to confirm the clear heat-shrinking bands are intact around each spout before filling.

ETC Bulletin 24-001 regarding Hot/Cold Beverage Kits has been archived and replaced by ETC Bulletin 25-001 for the 2025 season.

References:

NWCG Alerts

ETC-EB-25-001 Retrofitted Hot/Cold Beverage Kits

NWCG Standards for Wildland Fire Chainsaw Operations, PMS 212, and Next Generation Position Task Book for Basic Faller Are Now Available

Date: April 14, 2025
Questions?  Please contact:
Hazard Tree and Tree Felling Subcommittee

The updated NWCG Standards for Wildland Fire Chainsaw Operations, PMS 212, and NWCG Position Task Book for Basic Faller (FAL3), PMS 311-19 are now available.

The NWCG Standards for Wildland Fire Chainsaw Operations, PMS 212 includes position standards designed to be used in conjunction with the Next Generation Position Task Book (Next Gen PTB). The Next Gen PTB for Basic Faller (FAL3) includes an evaluation guide with suggested rating elements to consider when assessing trainees.

References:

NWCG Standards For Wildland Fire Chainsaw Operations, PMS 212

NWCG Position Task Book for Basic Faller (FAL3), PMS 311-119

NWCG Basic Faller (FAL3)

RMC Memo 25-01: Summary of Updates to Safety Officer Positions

Date: April 9, 2025
Questions?  Please contact:
RMC Member Eric Fransted

The Risk Management Committee (RMC) serves as the position steward for all Safety Officer incident positions and continues to improve position standards, training, and naming conventions. The implementation of Complex Incident Management (CIM) required changes to position titles. RMC collaborated with the NWCG Incident Position Standards Committee (IPSC) to propose and implement these updates. 

References:

RMC Memo 25-01: Summary of Updates to Safety Officer Positions 

NWCG Position Catalog