In each case he has taken soil, grain, and straw samples from inside and outside the circles. In the earlier instances, Clairmont says analysis of the samples showed a number of differences between samples taken inside and outside the circles, differences that point to sudden heating in the circles. Clairmont says he doesn't draw any conclusions from his investigations, but the results raise a lot of questions. I looked at the soil in the circles at Rocanville, and the ground isn't compacted at all. The stones aren't pushed into the ground.
Some people think it's just a whirlwind.
Clairmont took measurements, and found that the circles are not perfectly round. One, on a slight incline, has a diameter that ranges from 44.5 to 46.5 feet. The longer diameter runs along the incline, as would be expected if a circle was impressed from above. The other circle, on more level ground, has a diameter that varies from 45.5 to 46 feet. Clairmont isn't counting on his investigations ever turning up the source of the crop circles.