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PMS 437

Surface Fire Size and Shape

  1. Surface Fire Shape
  2. Surface Fire Area Estimation from Point Source Fire, in Acres
  3. Surface Fire Perimeter Estimation from Point Source Fire, in Chains

These tools are intended for use with initiating fires only. Use the known ignition time and the number of hours after that you are interested in. Consider using:

  • Number of hours from ignition until the end of the expected burn period.
  • Number of hours until you arrive at the fire.

Surface Fire Shape

Remember that effective windspeed, as referenced here, is based on midflame windspeed.

Length to Width Ratio in parenthesis

Surface Fire Elliptical Shape - These elliptical fire shapes demonstrate the effect of midflame windspeed and point out the length to width ratio in each case.

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Surface Fire Area Estimation from Point Source Fire, in Acres

Table 1, Spread Distance 1–50 Chains

Surface Fire Area, Table 1 (1—50 chains spread distance).

Table 2, Spread Distance 52–165 Chains

Surface Fire Area, Table 2 (52-165 chains spread distance).

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Surface Fire Perimeter Estimation from Point Source Fire, in Chains

Table 3, Spread Distance 1–50 Chains

Surface Fire Perimeter, Table 3 (1—50 chains spread distance).

Table 4, Spread Distance 52–165 Chains

Surface Fire Perimeter, Table 4 (52-165 chains spread distance).

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NWCG Latest Announcements

NEW! S-490, Advanced Fire Behavior Calculations (Blended) Available Now

Date:  March 17, 2026
Questions? 
Please contact: Fire Behavior Subcommittee

NWCG is pleased to announce that the new S-490, Advanced Fire Behavior Calculations (Blended), 2026 course is now available.

This training includes performance-based activities that allow students to apply the knowledge and concepts required for the Fire Behavior Analyst (FBAN), Long Term Fire Analyst (LTAN), and Prescribed Fire Burn Boss Type 1 (RXB1) positions. It supports individuals working towards these incident qualifications.

This blended course begins with a self-paced online training (OLT) in the Wildland Fire Learning Portal (WFLP), followed by an in-person instructor-led training (ILT).

References:

S-490, Advanced Fire Calculations (Blended)

NWCG Fire Behavior Analyst (FBAN) Position Page

NWCG Long Term Fire Analyst (LTAN) Position Page

NWCG Prescribed Fire Burn Boss Type 1 (RXB1) Position Page

2024 Paul Gleason Award Winners Announced

Date:  March 13, 2026
Questions? 
Please contact: Leadership Committee

The NWCG Leadership Committee is proud to announce the recipients of the 2024 Paul Gleason "Lead By Example" awards. Award categories include Initiative and Innovation, Mentoring and Teamwork, Motivation and Vision, as well as a Lifetime Achievement Award.

Congratulations to the awardees:

  • Justin Baxter, National Unmanned Aerial System (UAS) Operations Specialist, with the U.S. Forest Service — Initiative and Innovation
  • Kelly Woods, Director of the Wildland Firefighting Lessons Learned Center — Mentoring and Teamwork
  • Doug Booster, Instructor, ProHealth Net, Inc. — Motivation and Vision
  • Pam McDonald, Writer-Editor for the National Interagency Fire Center — Lifetime Achievement Award

References:

Paul Gleason Lead By Example Award

Wildland Fire Leadership Development Program (WFLDP)

Leadership Committee

NEW! S-231, Engine Boss Course Available Now

Date:  March 6, 2026
Questions? 
Please contact: Incident Operations Subcommittee

NWCG is pleased to announce the new S-231, Engine Boss (Single Resource) course is now available on the Wildland Fire Learning Portal (WFLP). Developed through the Incident Performance and Training Modernization (IPTM) effort, this training supports individuals working towards Engine Boss, Single Resource (ENGB) incident qualifications. 

This is a performance-based instructor-led training (ILT) that focuses on the application of ENGB responsibilities during wildland fire operations, emphasizing readiness, information gathering, risk management, engine tactics, and Wildland Urban Interface (WUI) operations. Trainees apply these skills through scenario-based group work and an optional field day that reinforces hands-on engine operation tasks. 

References:

S-231, Engine Boss (Single Resource) (Instructor-led)

NWCG Engine Boss, Single Resource (ENGB) Position Page

Wildland Fire Learning Portal

NWCG Celebrates 50 Years!

Date:  March 6, 2026
Questions? 
Please contact: NWCG Executive Secretary

NWCG is proud to celebrate 50 years of service to the wildland fire community. Beginning in 1976 with an interagency agreement between the Department of Interior and Department of Agriculture, NWCG has grown to include additional member agencies and is recognized as the standard-setting leader in wildland fire operations.

To honor where we’ve been and highlight where we are going, the NWCG team has created a video showcasing our history and accomplishments. The video is now available on the NWCG website.

References:

NWCG 50 Year Anniversary Video