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Extreme Fire Behavior – I

Changes in fire behavior have always been present in cases of shelter deployment. Firefighters maintain a heightened awareness of daily fluctuations in live and dead fuel moistures, along with current and predicted weather conditions. Other inputs like fuel type and topography add to the picture. Firefighters must cultivate a healthy respect for these factors. When fuel moistures, fuel type, weather conditions, and topography align, extreme fire behavior is likely. As fire behavior moves from mild to moderate to extreme, it is critical to recognize the changing situation and act appropriately.

Discuss the following factors that can contribute to extreme fire behavior:

  • Relative humidity less than 15%
  • 1-hour fuel moisture less than 5%
  • Transition from surface to crown fire
  • Light flashy fuels
  • Smoldering fires that exist in the early part of the day are beginning to burn very actively as the day progresses
  • Approaching thunderheads with dark clouds beneath
  • Presence of dust devils indicating atmospheric instability
  • Increased spotting
  • Sudden calm
  • Volatile fuel types
  • High clouds moving fast in a direction that is different from surface wind
  • Predicted high mixing height as an indicator of atmospheric instability and the potential for vertical column development
  • Fire whirls
  • Topography
     

Discussion Questions: 

  • What combination of conditions and local factors (weather, fuel type, fuel moisture, topography) on your home unit contribute to extreme fire behavior?
  • How might you adjust your tactical approach or objectives when those conditions are present? How do you balance this with Fire Order #10?
  • What actions can you take to keep calm, think clearly, and act decisively before and during sudden changes in fire behavior impacting your work area?
  • How do you communicate changes in fire behavior which could impact your crew? How are those messages passed to convey any necessary changes to operational tempo or urgency?
  • What terms are needed to paint a common operating picture of the fire behavior and rates of spread you’re seeing? (Work to get on the same page about what specific terms mean. Is the fire “pulsing” or “making a sustained run”? Are the spots “catchable” or “forming a new head fire”? Do you need to “adjust tactics”, or “adopt a new strategy”?)

References:

Fire Whirls video produced by Rocky Mountain Research Station 
Extreme Fire Behavior – II, 6MFS Topic
NWCG Incident Response Pocket Guide (IRPG), PMS 461, Common Denominators of Fire Behavior on Tragedy Fires, Operational Engagement (green)
 

Category
Operational Engagement, Weather - Fire Behavior

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NWCG Latest Announcements

Intermediate Faller (FAL2) Position Task Book Update

Date:  July 24, 2026
Questions? 
Please contact: Tree Felling Subcommittee

NWCG Operations Management Committee (OMC) has issued an update to the NWCG Position Task Book for Intermediate Faller (FAL2), PMS 311-91. To ensure clarity for both trainees and evaluators, the updated FAL2 Position Task Book (PTB) explicitly states who is authorized to sign off on your tasks:

“Evaluators must be qualified as a FAL2, or an Advanced Faller (FAL1).”

If you are currently working out of a previously published version of the FAL2 PTB, you do not need to restart. However, OMC highly encourages you to take the following step to prevent any confusion in the field:

  • Print and replace the updated evaluator information page (page 2) in your current physical PTB.

References:

Intermediate Faller (FAL2) Position Page

RMC Memo 26-01: Transition Plan for Implementing Updates to Intermediate Faller (FAL2) Position Qualifications

NWCG Position Task Book for Intermediate Faller (FAL2), PMS 311-91

Equipment Advisory 26-001: Potential Front Driveline Joint Failure on 2018 and Earlier Ram Pickups

Date:  July 10, 2026
Questions? 
Please contact: Equipment and Technology Subcommittee

The Logistics/Equipment Management Committee (LMC) has released Equipment Advisory 26-001: Potential Front Driveline Joint Failure on 2018 and Earlier Ram Pickups. This advisory highlights multiple U.S. Forest Service regions reporting front driveline joint failure incidents.

This advisory recommends firefighters and fire managers to: 

  • Follow all Ram-issued inspection, maintenance, and service guidance for front driveline joints. 
  • Consider installing a driveline loop. 
  • Coordinate with fleet managers and service providers to determine the most appropriate driveline loop kit for each pickup.

For further details, please refer to the complete advisory.

References:

Equipment Advisory 26-001: Potential Front Driveline Joint Failure on 2018 and Earlier Ram Pickups

Technical Service Bulletin: 03-002-21

NEW! NWCG Standard Operating Procedures, PMS 900

Date:  July 9, 2026
Questions? 
Please contact: NWCG Staff

NWCG is excited to announce the publication of the NWCG Standard Operating Procedures, PMS 900.

The new publication establishes general, consistent, and uniform standards for conducting business with the National Wildfire Coordinating Group.

References:

NWCG Standard Operating Procedures, PMS 900

Quarter Four Materials for the 2025-2026 Wildland Fire Leadership Campaign Now Available

Date:  July 8, 2026
Questions? 
Please contact: Leadership Development Subcommittee

NWCG is excited to announce that Fourth Quarter materials for the 2025/2026 Wildland Fire Leadership Campaign are now available. This annual initiative offers all students of leadership and wildland fire management an opportunity to engage with essential leadership skills and knowledge needed to lead effectively in dynamic environments.

Quarter Four materials focus on Leadership Level 4: Leader of Leaders (Provide Direction). Leadership Level 4 is where you are setting the conditions for others to do things well, even when you are not present. This quarter focuses on equipping experienced leaders with skills to provide direction, build trust across teams, and foster strong decision making. 

References:

2025/2026 NWCG Leadership Campaign - Leadership Levels

Wildland Fire Leadership Development Program

Leadership Development Subcommittee