photographer Helio C. Vital
"The cloud appeared about a half hour before sunset," says Vital. "It was part of a thunderstorm cell that was approaching, announcing the arrival of a new weather system that would bring rain to the city several hours later."
Meteorologists call this type of cloud a "tuba" -- a swirling mass of moist air that can hang down from an active thunderstorm. A tuba that touches the ground gets a new name: tornado. "Fortunately, in spite of its threatening appearance, this tuba did not reach the ground and no damage was reported," says Vital.
Click! was the correct choice after all.