Skip to main content

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

Image
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.

Return to Top

Surface Fire Area Estimation from Point Source Fire, in Acres

Table 1, Spread Distance 1–50 Chains

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

Table 2, Spread Distance 52–165 Chains

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

Return to Top

Surface Fire Perimeter Estimation from Point Source Fire, in Chains

Table 3, Spread Distance 1–50 Chains

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

Table 4, Spread Distance 52–165 Chains

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

Return to Top

Print PDF

NWCG Latest Announcements

Incident Position Standards and the Next Generation Position Task Books Now Available for PROC and TIME

Date: July 17, 2025
Questions?  Please contact:
Incident Business Committee

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for Procurement Unit Leader (PROC) and Time Unit Leader (TIME).

The Performance Support Packages for these positions 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 update, scheduled for January 2026.

References:

NWCG Procurement Unit Leader Position Page

NWCG Time Unit Leader Position Page

National Wildland Firefighter Day

Date: July 2, 2025
Questions?  Please contact:
National Interagency Fire Center

The National Wildfire Coordinating Group (NWCG) recognizes July 2, 2025, as National Wildland Firefighter Day (NWFFD). Established in 2022, NWFFD honors the dedication of wildland firefighters and support personnel. This day falls within the 2025 Week of Remembrance (June 30 - July 6), providing an opportunity to renew our commitment to wildland firefighter safety while remembering those who have fallen in the line of duty.

NWCG provides leadership to enable interoperable wildland fire operations among federal, state, local, Tribal, and territorial partners. NWCG standards and training establish common practices to contribute to safe, effective, and coordinated interagency wildland fire operations nationwide.

References:

Week of Remembrance

National Wildland Firefighter Day

2025 Week of Remembrance

Date: June 27, 2025
Questions?  Please contact:
6 Minutes for Safety Subcommittee

As we approach the 2025 Week of Remembrance (WOR), June 30–July 6, we dedicate this time to reflect on the past incidents from 2015 and honor the fallen through learning. Since its inception in 2014, WOR has honored wildland firefighters who made the ultimate sacrifice while encouraging critical discussions that reinforce lessons learned.

Throughout the week, we encourage thoughtful and generative conversations—whether in briefing rooms or at tailgates—that promote a culture of continuous learning and safety.

References:

2025 Week of Remembrance: Letter to Leadership

Wildland Fire Lessons Learned Center

ETC Equipment Bulletin: 25-003 Flame-Resistant Shirt Survey

Date: June 12, 2025
Questions?  Please contact:
Equipment Technology Committee

The U.S. Forest Service National Technology and Development Program (NTDP) is seeking input on the Forest Service-designed flame-resistant (FR) shirt, currently available through the National Interagency Support Cache system and FedMall.

NTDP is conducting a product review to improve future FR shirt designs. As part of this effort, a short survey is now open for federal employees who have worn any of three recent FR shirt models. Feedback will guide design improvements to better meet the needs of wildland firefighters.

To comply with the Paperwork Reduction Act, responses are limited to federal employees. The survey is open through September 12, 2025. 

References:

NWCG Alerts

ETC Equipment Bulletin: 25-003