In general, I’d agree with you about shorter brush enabling faster forward motion, but when the wind is up like this, the flame front gets blown right across the top.
After ignition is when the height and density of the brush comes into play because it determines how “deep”(thick) the flame front gets (taller brush, “deeper”/thicker flame front), which influences how hot the it gets (thicker front, hotter peak temp), which determines how far in advance of the main body of flames the heatwave can be pushed by the winds and ignite combustible materials.
P.S. I’m not interested in continuing the argument with your “expert” opinion, okay?
True. But it looked to me that the wind resistance caused by the height of the brush ahead of the fire front could affect the horizontal speed of the wind driving the flame. Smaller wind resistance with lower brush. What is causing problems here now is wind driven flames. Not brush driven flames. In brush driven flames we see many large fire tornadoes. Only saw a few small ones the past two days. I think you are entirely correct however for most of the brush fires we have had in the past. Those have had massive fire fronts and moved slow. What we are seeing now is a different beast. Fast moving with a low profile.