Christine Lemke, age 11, of Omaha, Nebraska, for her question:

What causes a hurricane?

Hurricanes hatch near, but not directly on, the equator and the weather conditions in these regions may suggest what causes them. Their breeding grounds are vast warm oceans, where the northeast and southeast trade winds arrow toward the equator. Embryo hurricanes start to form when long hours of tropical sunshine beat down on the water and fill the air with loads of vaporous moisture.

Such conditions cause great bubbles of light, warm air to rise aloft. The currents of ascending air draw in the surrounding heavier air. Other factors may or may not encourage this breezy pocket to develop into a full blown hurricane. The motion of the spinning earth veers the flowing air to spiral inward. At certain seasons, the north or south trade winds may bulge across the equator. Since they arrow together from different directions, they may add the extra swirl that helps a hurricane to graduate to full force.