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Replacing Haines Index and Lightning Activity Level

Background

The National Wildfire Coordinating Group (NWCG) Fire Weather Subcommittee (FWS) has recommended discontinuing the use of Haines Index (HI) and Lightning Activity Level (LAL) in fire weather forecasts and in NWCG training and curricula. A transition plan has been built to help firefighters understand what weather metrics to assess and how to brief all levels in the chain of command for the 2025 fire season.

Why are these fire weather metrics being replaced?

The HI is unsupported by research in predicting large fire growth and it is not a metric of atmospheric stability. Additionally, LAL is a duplicate of the thunderstorm coverage product that is already in the fire weather forecasts. The decision process included extensive interagency coordination and discussion as well as evaluation of peer-reviewed research.

Mixing Height

  • Mixing Height is the best current metric to replace HI.
  • Answers the question: how high in the atmosphere will rising air (fire column/smoke) ascend freely.
  • Mixing Height and Mixing Depth are interchangeable terms.
  • Mixing Height can indicate the ability of the atmosphere to support ascent of smoke and fire columns and conversely, resistance to vertical motion.
  • WHERE TO FIND: Spot Weather Forecast Discussions, Fire Weather Forecast discussions, and Fire Weather Dashboard (limited to 72 hours).

Mixing Height graph 72 hour limit.

Chance of Precipitation Crosswalk

  • Combining working in the Chance of Precipitation and Chance of Wetting Rain are the best resources (combined) to replace LAL.
  • Assessing the Potential for Lightning:
    • Are thunderstorm chances (in %) given in Sky/Weather section?
    • A higher percentage means higher odds for storms and lightning.
    • Compare to Chance of Wetting Rain (CWR). A high thunderstorm chance with low CWR may imply dry thunderstorms.
    • Remember any thunderstorm can lead to ignitions from lightning.
  • WHERE TO FIND: Chance of Precipitation and Chance of Wetting Rain from Fire Weather Planning Forecast, Spot Weather Forecast, and Fire Weather Dashboard.

References:

Category
Weather - Fire Behavior

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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: 

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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

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Questions? 
Please contact: NWCG Staff

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References:

NWCG Standard Operating Procedures, PMS 900

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Questions? 
Please contact: Leadership Development Subcommittee

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References:

2025/2026 NWCG Leadership Campaign - Leadership Levels

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Date:  June 30, 2026
Questions? 
Please contact: 6 Minutes for Safety Subcommittee

As we approach the 2026 Week of Remembrance (WOR), June 30–July 6, we dedicate this time to reflect on past incidents from 2016 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.

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References:

2026 Week of Remembrance: Letter to Leadership

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