Digital video analysis of smoke movement: an opportunistic proof of concept

On 30 September 2014, a metal fabrication plant across the street from the Pacific Wildland Fire Sciences Laboratory, in Seattle, caught fire. The fire occurred on a calm, clear day, and we recorded video of the event on a personal phone. Using standard image analysis techniques, we examine the video to determine the vertical velocity structure of the air in the smoke plume. Although this is a structural fire and not a wildland fire, the basic plume structure near the ground should be similar to that in a wildland fire. Visual examination at the time of the fire, and the recorded video, show clear evidence of acceleration and ring vortices moving up the column.

While the video is not professional quality and has limitations (e.g., file format, drift and jiggle because it was hand-held), the context also provides control of a number of factors more difficult in a wildland or prescribed fire context. The physical boundaries of the plume at the ground are constrained by the sides of the building; there is little wind to move the smoke away quickly; the distance between the camera and the plume are narrowly constrained.