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1/ #WlldlandFire @RateofSpread? What is #ROS? @CAL_FIRE definition: ROS defined as rate at the flame front advances thru the fuel. Can be measured in MPH or feet per minute, etc.
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2/ • Measurement Terms of ROS
• Low (slow) - very little spread, spread of no consequence
• Moderate - spread less than 1 MPH
• Dangerous - spread is 1-3 MPH
• Critical - over 3 MPH
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• Low (slow) - very little spread, spread of no consequence
• Moderate - spread less than 1 MPH
• Dangerous - spread is 1-3 MPH
• Critical - over 3 MPH
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3/ • The ROS influences the choice and timing of control actions.
• The ROS influences safety.
- How soon will the fire threaten personnel or equipment?
- When might potential escape routes be cut off?
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• The ROS influences safety.
- How soon will the fire threaten personnel or equipment?
- When might potential escape routes be cut off?
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4/ ROS related to how fast you can walk & maybe escape a rapidly spreading wildfire. A person walking fast at 4 MPH covers 352 ft in one minute. If slope is in play & walking speed reduces to 2 MPH, the #FF will cover 176 ft in one minute.
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5/ Focus on a Critical ROS fire burning at 3 or 3+ MPH & think if you can out walk or run the fire. Naw. Won't happen particularly light flashy fuels like grass fires. You must be on your game. Fire burns 17 times faster uphill than downhill without any wind advantage.
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6/ You must be on your game & consider ROS vs. your ability to find a #TemporaryRefugeArea or #SafetyZone. Fire won't quit, won't get winded, doesn't tire when the slope increases & won't give up...
Summary of ROS
