The stream plowed through the spewing clouds like a bullet through an apple, and hit a second thermopause. There was another fantastically powerful explosion. There was still no trace of wind at ground level, but the sound from that first overhead explosion reached the earth then, a cataclysmic roll of thunder that did not vary and did not stop. A cottonwood tree at the side of the road trembled violently, for no visible reason, so violently that it shed all its leaves.