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8.7 Slope Effect on ROS

When fire moves upslope, the fuel ahead of the flame front is closer to the flame than if the slope were flatter.  This set-up "preheats" the fuels. The effects of slope on fire spread become greater as the slope increases. 

graphic showing slope effects on fire

APPROXIMATING THE ROS

An easy guide for approximately the ROS due to changes in slope is as follows:
1. The first tripling of slope roughly increases the rate of fire spread by a factor of 2. 
2. The second tripling of slope increases the rate of spread by a factor of 4 to 6, depending on fuel conditions. 

The effect of an increase in slope on ROS depends both on the absolute slope as well as on the midflame wind speed. See Section 8.2 for more information on midflame and "effective" wind speeds.

Example 1 - An area of shrubs is burning at a ROS of 4 chains per hour at an 8 percent slope. The slope increases to 24 percent. What will the ROS be? 

Step 1. How much did the slope change? The slope percent increased from 8 percent to 24 percent. This change represents an increase of three times the original slope.

Step 2. How much will this slope change affect the ROS? As stated above, a tripling of slope increases the ROS by a factor of 2. 
2 × 4 chains/hr = 8 chains/hr
 

4 chains/hr × 2 = 8 ch/hr

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