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8.6 Head, Flank, and Rear Fire Terms

Each side of the fire is described in terms of head, flank, and rear. The head is the fastest spreading part of a fire's perimeter. The head is usually the side toward which the wind is blowing, and will also often be the upslope side of a fire. The head of the fire is of primary interest. 

The right and left flanks describe the sides of the fire. Flanks are perpendicular to the head of the fire. 

The rear of the fire is the side of the fire opposite the head.
 

screengrab of animation of fire spread
Click on the graphic above to view animation of fire spread along head, flank, and rear

Example 1 - Plot the perimeter and label the head, rear, and flanks of a fire with ROS of 4 chains/hour and PT of 3 hours. Assume the wind is blowing from left to right across the page.  
 

flank image

The head of the fire on your drawing should correspond to the edge of the fire's forward perimeter at the projection time. The distance from head to rear will correspond to the spread distance, in this case 12 chains.

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Contact: NWCG Webmaster

The National Wildfire Coordinating Group is thrilled to announce a significant upgrade to https://www.nwcg.gov, involving a comprehensive redesign of over 7,000 web pages. This enhancement is focused on improving user experience. The migration to the new NWCG website will commence on April 2, 2024, starting at noon EST and is expected to take a few hours. 

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WFSTAR 2023 Year in Review and 2024 Core Component Module Packages Available

Date: March 6, 2024
Contact: Joe Schindel 

The 2023 Fire Year in Review module and 2024 Core Component Module Packages for RT-130, Wildland Fire Safety Training Annual Refresher (WFSTAR) are now available on the NWCG website. The 2024 Core Component Module Package provides all content needed to deliver RT-130.

 

References:

WFSTAR 2023 Fire Year in Review module

WFSTAR 2024 Core Component Module Packages

2024 NWCG Executive Board Annual Letter

Date: March 6, 2024
Contact: NWCG

The NWCG Executive Board is privileged to share with you the 2024 NWCG Executive Board Annual Letter. As we look into the future and navigate an incredibly complex and dynamic environment, we must remain focused on our mission while actively engaging in national conversations regarding numerous wildland fire initiatives. In 2024, we prioritize building upon our successes and committing to continuous improvement. Key priorities and considerations for this year include: 

  • Determining Core Workload
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Together we will continue to make significant strides in the challenging and vital work that lies ahead. 

 

References:

2024 NWCG Executive Board Annual Letter

NWCG Welcomes NASA

Date: February 22, 2024
Contact: NWCG

NWCG welcomes the National Aeronautics and Space Administration (NASA) as an associate member.

“As wildfires become larger and more frequent, NASA is working to apply our scientific and technological knowledge toward this national challenge, and integral to our approach is forging collaborative partnerships,” said NASA Deputy Administrator Pam Melroy. 

 

References:

NASA News Release

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