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Surface Fire: Vectoring Fire Behavior

Projecting fire spread with cross slope winds utilizes a vectoring process, where the effect of wind and the effect of slope on Rate of Spread (ROS) may be represented by separate vectors that represent both a magnitude and a direction. The resultant vector represents both a direction and magnitude of maximum spread in that direction.

  1. Slope Vector is drawn directly upslope and estimated by calculating ROS with the estimated slope steepness and Zero (0) windspeed for inputs.
  2. Wind Vector is drawn in the direction of the wind and estimated by calculating ROS with the estimated windspeed and Zero (0) slope.
  3. Maximum Spread Vector can be drawn as shown and measured to determine the resultant ROS and spread direction.
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Vectoring Wind and Slope Example - Examples of vector addition to combine the influences of wind and slope on the resulting speed and direction of fire spread.

In example A here, wind is crossing more upslope, resulting in an enhanced maximum ROS.

In example B, wind is crossing more downslope, resulting in a reduced maximum ROS.

With winds blowing downslope (±30°), the difference between the spread rates is the resulting ROS using the direction from the larger vector.

If the vectoring process is completed manually:

  • ROS is determined from the measured maximum spread vector (spread distance) and the time period used to obtain wind and slope vector estimates.
  • Heat Per Unit Area (H/A) is the same for all component vectors.
  • Fireline intensity (FLI) and flame length (FL) can be calculated from ROS and Heat Per Unit Area (HPA) using these calculations.

FLI = (ROS * HPA)/55

FL = .45 * FLI.46

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Incident Position Standards and Next Gen Position Task Books Now Available for Dispatch Incident Positions

Date: March 5, 2025
Contact: National Coordination System Committee

NWCG is excited to announce that Incident Position Standards and Next Generation Position Task Books are now available for all six Dispatch positions:

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The Performance Support Packages for these positions, including the Expanded Dispatch Job Aid, J-601 and the Initial Attack and Aircraft Dispatcher Job Aid, J-602, were developed as part of the Incident Performance and Training Modernization (IPTM) effort. These resources support trainees, qualified personnel, and evaluators in their roles.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1.

References:

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Incident Position Standards and the Next Generation Position Task Books Now Available for DMOB, DOCL, and RESL

Date: February 28, 2025
Contact: Incident Operations Subcommittee

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for Demobilization Unit Leader (DMOB), Documentation Unit Leader (DOCL), and Resources Unit Leader (RESL).

The Performance Support Packages for these positions, including a job aid for RESL, were developed as part of the Incident Performance and Training Modernization (IPTM) effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1.

References:

NWCG Demobilization Unit Leader Position Page 

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Next Generation Position Task Book and Updated Incident Position Description Now Available for Operations Section Chief Complex

Date: February 27, 2025
Contact: Incident Operations Subcommittee

NWCG is excited to announce that Operations Section Chief Complex (OSCC) has a Next Generation NWCG Position Task Book for Operations Section Chief Complex (OSCC), PMS 311-108 and an updated Incident Position Description.

These resources support trainees, qualified personnel, and evaluators in their respective roles.

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NWCG Operations Section Chief Complex Position Page 

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NWCG Position Task Book for Operations Section Chief Complex (OSCC), PMS 311-108 

2025 NWCG Incident Response Pocket Guide (IRPG), PMS 461, Now Available

Date: February 27, 2025
Contact: Incident Operations Subcommittee

NWCG is excited to announce that the 2025 NWCG Incident Response Pocket Guide (IRPG), PMS 461, is now available. Visit NWCG's website to learn about the major updates and changes in the 2025 version of the IRPG. The NWCG Guia de Respuesta de Incidente de Bolsillo (GRI), PMS 461-ES is available electronically and will be available from Great Basin Cache by early summer 2025.

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NWCG Incident Response Pocket Guide (IRPG), PMS 461 

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