On the evening of April 6th, the smoke plume from a scrap yard fire at the Miller Compressing Company in Milwaukee demonstrated how wind direction changes with height. Mark Was, a photographer from WTMJ TV-4, was able to capture an aerial picture of the plume illustrating the meteorological phenomenon.
On this particular evening, the average wind in the near surface layer of the atmosphere was southeasterly, farther up in the atmosphere winds began to shift to a more westerly, and then northwesterly direction. In the picture below, the smoke plume from the fire appears to be traveling in a uniform direction near the surface. However, the plume does not continue in the same direction throughout its entirety. Rather, the direction the smoke plume is moving changes with height, in conjunction with the change in wind direction.
The image below shows the source of the fire and a portion of the smoke plume in the lower levels of the atmosphere.
Click on either image for a larger version.