A well defined lowering appeared under the rotating storm base. The rotation concentrated in this area spinning up dirt circulations on the ground. The two circulations pictured here were strong enough to be considered weak tornadoes. The rotation at cloud base was reaching tornadic speed. This show would persist until after sunset.
Dirt is flung violently as the tornado begins to take shape.
The forming funnel is the bulbous lowering in the center of the image. A mass of rotating dirt was all that could be seen under the mesocyclone soon after this shot was taken. So many times chasers witness a forming tornado in the waning minutes of daylight. I could see the tornado quite well in the fading twilight. A block of rotating dust persisted into the darkness.