Skip to main content

PMS 437

Weather: Stability

  1. Measures of Stability
  2. Lower Atmospheric Stability (Haines) Index

Measures of Stability

Index Major Factors Primary Utility Application
Davis Stability Index Lapse rate Basic measure of stability Southeast US
Ventilation Index Mixing height and transport wind Smoke dispersion United States
Haines (Lower Atmospheric Stability) Index Lapse rate and relative humidity Large fire growth potential United States
Pasquill Stability Index Solar radiation, cloud cover and surface wind speed (surface based stability) Smoke dispersion SASEM
Lavdas Atmospheric Dispersion Index Pasquill, mixing height, transport wind Smoke dispersion and fire growth potential. Florida

Return to Top

Lower Atmospheric Stability (Haines) Index

The Lower Atmospheric Severity Index, commonly known as the Haines Index, was developed during the 1980s as a fire weather tool to estimate the effect of atmospheric dryness and stability on the growth potential of a wildfire. The goal was to identify typical combinations of humidity and stability and contrast them with combinations of stability and humidity prevalent during problem fire outbreaks. Always reference local Climatology, see below.

Haines Index Calculation Criteria

LOW ELEVATION Stability Term (A) LOW ELEVATION Moisture Term (B)
950 – 850 mb °C
A = 1 when 3°C or less
A = 2 when 4-7°C
A = 3 when 8°C or more		 950 mb T° C – 950 DP° C
B = 1 when 5° C or less
B = 2 when 6-9° C
B = 3 when 10° C or more
MID ELEVATION Stability Term (A) MID ELEVATION Moisture Term (B)
850 – 700 mb °C
A = 1 when 5°C or less
A = 2 when 6-10°C
A = 3 when 11°C or more		 850 mb T° C – 850 DP° C
B = 1 when 5° C or less
B = 2 when 6-12° C
B = 3 when 13° C or more
HIGH ELEVATION Stability Term (A) HIGH ELEVATION Moisture Term (B)
700 – 500 mb °C
A = 1 when 17°C or less
A = 2 when 18-21°C
A = 3 when 22°C or more		 700 mb T° C – 700 DP° C
B = 1 when 14° C or less
B = 2 when 15-20° C
B = 3 when 21° C or more
Haines Index (A + B) Potential for Large Fire
2 or 3
4
5
6		 Very Low
Low
Moderate
High

U.S. Haines Elevation Classification Map

The Haines, or Lower Atmospheric Stability Index, uses different inputs based on the general classification of terrain elevation. This map displays areas of High, Mid, and Low elevation areas.

Haines Index Climatology

Print PDF

NWCG Latest Announcements

Updated NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515

Date: May 10, 2024
Contact: IFUASS Qualification and Curriculum Board (IFUASS) 

The 2024 revision of the NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515 is now available. PMS 515 standardizes the processes and procedures for interagency use of Unmanned Aircraft Systems (UAS), including pilot inspections and approvals. This publication is now available as a PDF for easy use offline.

References:

NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515

Memorandum 24-003: Removal of Type 1 Command and General Staff (C&G) Incident Position Qualification Pathways

Date: May 10, 2024
Contact: Aitor Bidaburu 

The purpose of this memorandum is to provide NWCG direction for removal of the Type 1 Command and General Staff (C&G) incident position qualification pathways to transition to Complex Incident Management (CIM). Responders may continue to utilize available NWCG pathways to attain Type 1 C&G qualifications until December 31, 2024.

References:

Memorandum 24-003

CIM Story Map

2024 Professional Reading Program

Date: April 26, 2024
Contact: Wildland Fire Leadership Development Program (WFLDP) 

The Wildland Fire Leadership Development Program is announcing the 2024 Professional Reading list! The intent of the Professional Reading Program is to promote the reading and discussion of these books throughout the year. Discussion guides are provided and the corresponding Wildland Fire Leadership Levels have been identified.

The five books chosen for this year are: Young Men and Fire by Norman Maclean, The Wisdom of the Bullfrog by William H. McRaven, The Art of Clear Thinking by Hasard Lee, Emotional Agility by Susan David, and Writing to Persuade by Trish Hall.

References:

Professional Reading Program

Wildland Fire Leadership Levels

NWCG Training Catalog now on Wildland Fire Learning Portal

Date: April 25, 2023
Contact: NWCG Training  

The National Wildfire Coordinating Group (NWCG) has migrated the training catalog from the NWCG website to the Wildland Fire Learning Portal (WFLP) as part of our ongoing efforts to streamline processes and improve efficiency. To facilitate this transition, the training catalog remains available on www.nwcg.gov through April 2024.

Starting May 2024, the training catalog will no longer be accessible on www.nwcg.gov. However, you can still access the complete training catalog by logging in as a guest to the WFLP.

References:

Wildland Fire Learning Portal