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Safety Zone Research

Please watch the video below for this subject:

WFSTAR: Latest Research on Estimating Safety Zones (Time 6:15)


First, a Fire Behavior 101 refresher:  You can warm yourself around the sides of a campfire for quite some time; that’s radiant heat. If you hold your hands over the top of the fire, you’ll get burned relatively quickly; that’s convective heat.

Basically, wind or slope can tip the flames over, so that the convective heat is no longer going straight up, but is now aimed more along the ground, sending the heat and hot gasses much further ahead. This causes preheating of the fuels, faster fire spread, and greater fire intensities. You’ll need a larger safety zone if that fire is coming towards you.

The current equation for safety zone size on the Safety Zones page of the Incident Response Pocket Guide (IRPG), PMS 461:

4 x Flame Height = Safe Separation Distance

To make estimations of flame height though, you either have to use past fire behavior observations or use your experience to guess what the fire may do in the future. After a decade of research, Bret Butler, at the Missoula Technology and Development Center, suggests removing the uncertainty and guesswork that comes with estimating flame height by taking the general rule of thumb:

Flame Height = 2 x Vegetation Height

…and substituting that Flame Height equation into the original IRPG equation, to give:

4 x 2 x Vegetation Height = Safe Separation Distance, which simplified is:
 8 x Vegetation Height = Safe Separation Distance

But remember, that’s still for radiant heat only, on flat ground, with no wind. To take into account the convective heat from slope or wind, Butler’s research suggests that a Slope Wind Factor is needed in the equation:

8 x Vegetation Height x Slope Wind Factor = Safe Separation Distance

But what is the Slope Wind Factor? Current research is indicating that the Slope Wind Factor is between 1 and 10, with Butler arguing it may be closer to between 1 and 5. Butler’s ongoing research is focused on answering that question by gathering sensor data on fires, running computer simulations, and refining the models.

In the meantime, utilize the calculations in the Safety Zones page of your IRPG to help you determine a bare minimum size for your safety zone with the understanding that slope and wind need to be considered in your decision-making.

But remember, a safety zone is only good if you can get there.

References:

Category
Operational Engagement

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NWCG Latest Announcements

2026 Updates to the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1

Date: January 23, 2026
Questions? 
Please contact: Incident and Position Standards Committee

The Incident and Position Standards Committee has updated the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1.

These updates address changes to incident position names and requirements for qualification, training, and experience. Updates related to the implementation of Complex Incident Management (CIM) and Incident Performance Training Modernization (IPTM) are also included.

The NWCG Wildland Fire Position Qualification Flowchart, PMS 308 has also been updated to reflect the recent changes.

References:

NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1

NWCG Wildland Fire Position Qualification Flowchart, PMS 308

IPSC Memo 26-01: January 2026 Updates to the NWCG Standards for Wildland Fire Positions Qualifications, PMS 310-1

Incident Business Committee Memo 26-01: Updated Emergency Equipment Shift Ticket, OF 297

Date: January 22, 2026
Questions? 
Please contact: Incident Business Committee

The Incident Business Committee (IBC) has released Memorandum 26-01: OF 297 and 2026 Fire Use. This memo informs the wildland fire community that the updated Emergency Equipment Shift Ticket, OF 297 is available for download and can be ordered through the Great Basin Cache.

Beginning January 15, 2026 the previous version of the OF 297 form has been discontinued.

For further details, please contact your IBC representative.

References:

Incident Business Committee Memorandum 26-01

Great Basin Cache

NEW! S-390, Introduction to Wildland Fire Behavior Calculations (Blended) Available Now

Date: December 22, 2025
Questions about RT-130? 
Please contact: Fire Behavior Subcommittee

NWCG is excited to announce that the new S-390, Introduction to Wildland Fire Behavior Calculations (Blended) training is now available on the Wildland Fire Learning Portal.

This third course in the series combines online and instructor-led training components aimed at individuals who are involved in planning, managing, and executing wildland fire and prescribed burn operations; who require a thorough understanding of fire behavior calculations to enhance effectiveness and safety. This includes students who require the knowledge and skill necessary to perform the duties of a Type 3 Incident Commander (ICT3), Division/Group Supervisor (DIVS), or Prescribed Fire Burn Boss Type 2 (RXB2).

Students are required to be qualified as any Single Resource Boss position and complete the prerequisite S-290, Intermediate Wildland Fire behavior (Blended) course, before enrolling in S-390.

References:

S-390, Introduction to Wildland Fire Behavior Calculations (Blended)

Wildland Fire Learning Portal

NEW! S-320, Introduction to Incident Management Teams (Blended) Available Now

Date: December 18, 2025
Questions about RT-130? 
Please contact: Incident and Position Standards Committee

NWCG is excited to announce that S-320, Introduction to Incident Management Teams (Blended) is now available on the Wildland Fire Learning Portal!

This blended course combines online learning with instructor-led training, designed for individuals seeking to build leadership skills and gain experience in incident management.

Students are required to complete the prerequisite trainings ICS-100, Introduction to Incident Command System (ICS), ICS-200, Basic ICS for Initial Response, and ICS-700, An Introduction to the National Incident Management System (NIMS) prior to attending S-320.

References:

S-320, Introduction to Incident Management Teams (Blended)

Wildland Fire Learning Portal