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Extreme fire behavior captured by Digital Infrared Imager
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| Our September 4th flight took us over the McDonald Creek fire, which was moving up a shallow canyon. The remarkable set of images below show a dramatic example of the dynamics within wildfires. | |
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The "Finger of Death" The sequence of 6 images to the left (spaced 0.75 seconds apart) come from the Inframetrics Thermacam. (Data from the Thermacam is obtained every 1/30 of a second.) The brightest color (yellow) is the hottest. This sequence shows that a"finger of death" burst forward about 100 m from the head of the fire at speeds exceeding 100 miles per hour, and retreats back into the fire within 3 seconds. Seven horizontal rolls and capping vortices are also identified in the 3rd frame. Horizontal rolls within fires have been hypothesized as occurring with crown fires, but to our knowledge, have not previously been detected. |
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| An EDRIS (Extended Range Imaging Spectrometer, operated by NASA) image shortly after the sequence above shows that the burst was indeed along the ground, and left a path of ignited fuel (identified by the big arrow) after its retreat. | Plan view from above of the temperatures detected by the infrared videocamera. The brightest colors (yellow) are hottest. The fire is advancing towards the bottom of the frame. Vigourous combustion is occuring in the L-shaped hot region. The arrows show air motions detrived from the imagery through image flow analysis, after airplane motions are removed. Vigorous air motions of over 20 m/s were consistently found. |
Last Modified: 21 Jul 2000