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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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Date:  May 28, 2026
Questions? 
Please contact: Risk Management Committee

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Date:  May 15, 2026
Questions? 
Please contact: Dispatch Position and Curriculum Management Subcommittee

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References:

D-110, Expanded Dispatch Recorder (Instructor-Led)

Expanded Dispatch Recorder (EDRC), Position Page

NWCG Incident Position Standards for Expanded Dispatch Recorder, PMS 350-59

Wildland Fire Learning Portal

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Date:  May 8, 2026
Questions? 
Please contact: Leadership Committee

The NWCG Leadership Committee promotes and enables leadership development across the wildland fire service. The committee provides education, training opportunities, and support for leadership innovation and best practices throughout the community.

A new IAP flyer is now available on the committee website, offering an overview of the products, curriculum, and learning opportunities the Leadership Committee develops. This resource is ideal for posting in your office, sharing with new employees, or distributing through your incident management teams to engage new voices in the leadership journey and reinforce a culture of self‑reflection, development, and growth.

References:

Leadership Committee 2026 IAP Flyer

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Date:  May 7, 2026
Questions? 
Please contact: Incident Operations Subcommittee

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See IOSC Memorandum 26‑01: Transition Plan for Implementation of Updates to the NWCG Position Task Book for Firefighter Type 1 (Squad Boss) (FFT1), PMS 311‑14 for more information.

References:

IOSC Memorandum 26-01: Transition Plan for Implementation of Updates to the NWCG Position Task Book for Firefighter Type 1

NWCG Firefighter Type 1 Squad Boss Position Page