140 likes | 301 Views
Fire Blow-Up Modeling: Implications for Situational Awareness & LCES. Jo Ann Fites Adaptive Management Services Enterprise Team, USDA Forest Service. Overview. Importance of fire accelerations in fatality fires Near misses? Modeling canyon blow-ups Test on Rattlesnake fatality fire
E N D
Fire Blow-Up Modeling:Implications for Situational Awareness & LCES Jo Ann Fites Adaptive Management Services Enterprise Team, USDA Forest Service
Overview • Importance of fire accelerations in fatality fires • Near misses? • Modeling canyon blow-ups • Test on Rattlesnake fatality fire • What does this mean for situational awareness & LCES?
Fire Fatalities & Blow ups What is common to loop, rattlesnake, south canyon, Cramer and others? • Numerous fire fatalities from blow-ups • Especially in drainages or canyons or “chimney’s” • Easily recognized but how fast can blow-ups occur? • Does the speed sink in?
Modeling Canyon Blow-Ups • Holding your finger near a match • Viegas canyon blow-up model • Based on laboratory tests • Mathematical landscape application • Tested with rx burn in chaparral • Viegas applied to several fatality fires in US • Future: predicting when blow-ups occur?
Rattlesnake Fire - Test • 1953 on Mendocino National Forest • 15 fatalities • Acceleration in small drainage a key factor • “Sundowner winds a factor” • Applied Viegas model
Viegas model simulation 2 versions tested 1 – simple 2 – canyon angles Assumptions: winds 3m/s, alpha=.000045
Follow the leader or model? • Model is useful but cannot substitute for the computer with slides in their head • (if it will blow-up)
Applications • What are the implications? • LCES • How much time do you have • for egress? • What are your triggers? • Chuck Hartley • when fire hits the bottom it is time to • go..not wait and see what happens • But this depends on the situation
structures Codfish fire 13 45 Sz? • Egress times for crews from bottom of canyon vs potential speed of fire up chimneys? • 45 min. out for hotshot crews • Accel. times of 13 to 50 minutes 40
Operations 1) Where might it escape, size of WFSA -does the box need to be bigger? 2) overall hazard awareness for resources - improve situational awareness - not a substitute but some means of a “slide” for inexperienced crews 3) egress: - info to compare egress time estimates - setting triggers – go when it is at the bottom no matter what the size of fire 4) spacing of safety zones Have to rely 1st upon good, experienced leadership & what is going on at the fire (Codfish – Rax – “I told you it would not reach your sensors” --this tool is supplemental