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Extreme Fire Behavior – I

 

Fire managers make decisions throughout the day on how to suppress fires and best use resources while protecting life and property. This Standard Firefighting Order depicts a firefighter observing increased fire behavior during a time of day when temperatures are high and relative humidity is low.

3. Base all actions on current and expected behavior of the fire. A firefighter looks at his watch, which reads 2 PM, while a fire actively grows in steep terrain and heavy timber.

3. Base all actions on current and expected behavior of the fire.

Read about all 10 Standard Firefighting Orders.

Changes in fire behavior have always been present in cases of shelter deployment. It is critical for firefighters to maintain situation awareness of live and dead fuel moisture conditions, as well as predicted and current weather conditions. As fire behavior moves from mild to moderate to extreme, it is critical to act decisively regarding the changing situation.

Discuss the following indicators of extreme fire behavior:

  • Relative humidity less than 15%.
  • 1-hour fuel moisture less than 5%.
  • Transition from surface to crown fire.
  • 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.
  • High clouds moving fast in a direction that is different from surface wind.
  • Predicted Haines Index of 5 and 6 in those areas where this level is a good indicator of atmospheric instability.
  • Fire whirls.

Image of a fire whirl twisting up from a forest fire.

 

Category
Weather Fire Behavior

Last Modified / Reviewed:


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NWCG Latest Announcements

Great Basin Cache Upgrading to New Inventory System

Date: May 7, 2025
Questions?  Please contact:
Great Basin Cache
Phone: (208) 387-5104
Fax: (208) 387-5573

The Great Basin Cache (GBK) is transitioning to a new inventory system to better serve the wildland fire community. During this upgrade, GBK will be unable to process standard orders from Part 1: Fire Supplies and Equipment and Part 2: Publications between May 8-20, 2025, with exceptions made for emergency fire orders. Orders will be accepted through close of business May 7.

To browse the latest available items, please refer to the National Fire Equipment System (NFES) catalogs. 

References:

NWCG NFES Catalog-Part 1: Fire Supplies and Equipment, PMS 449-1

NWCG NFES Catalog-Part 2: Publications, PMS 449-2

NEW! Air Operations Summary (ICS 220 WF) Now Available

Date: May 2, 2025
Questions?  Please contact:
National Interagency Aviation Committee

The Air Operations Summary (ICS 220 WF) provides the Air Operations Branch with the number, type, location, and specific assignments of helicopters and air resources. The new ICS 220 WF also includes medical extraction capabilities and air resources tracking.

Understanding the capabilities of aviation assets is critical for effective medical and extraction responses. Coordination with the Medical Unit Leader is essential to ensure alignment and consistency between the ICS 220 WF and the Medical Plan (ICS 206 WF). 

References:

Air Operations Summary (ICS 220 WF)

National Interagency Aviation Committee

Incident Command System (ICS) Forms

Incident Position Standards and Next Generation Position Task Book Available for Firing Boss, Single Resource

Date: April 30, 2025
Questions?  Please contact:
Fuels Management Committee

NWCG is excited to announce that the NWCG Incident Position Standards for Firing Boss, Single Resource, PMS 350-105, and the NWCG Position Task Book for Firing Boss, Single Resource (FIRB), PMS 311-105, are now available. 

These resources, part of the Performance Support Package developed through the Incident Performance and Training Modernization (IPTM) effort, support trainees, qualified personnel, and evaluators. 

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 Firing Boss, Single Resource Position Page

NWCG Incident Position Standards for Firing Boss, Single Resource, PMS 350-105

NWCG Position Task Book for Firing Boss, Single Resource (FIRB), PMS 311-105

Incident Position Standards and Next Generation Position Task Book Available for Helicopter Crewmember

Date: April 28, 2025
Questions?  Please contact:
Interagency Helicopter Operations Subcommittee

NWCG is excited to announce that the NWCG Incident Position Standards for Helicopter Crewmember, PMS 350-22, and the NWCG Position Task Book for Helicopter Crewmember (HECM), PMS 311-22, are now available.

These resources, part of the Performance Support Package developed through the Incident Performance and Training Modernization (IPTM) effort, support trainees, qualified personnel, and evaluators.

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 Incident Position Standards for Helicopter Crewmember, PMS 350-22

NWCG Incident Position Standards for Helicopter Crewmember, PMS 350-22

NWCG Position Task Book for Helicopter Crewmember (HECM), PMS 311-22