|MadSci Network: Earth Sciences|
Hurricanes do not cross the equator. The atmosphere at the equator is relatively calm. Storms that approach the equator have a very hard time sustaining their winds within 5 degrees of the equator. Tropical cyclones that move into these very low latitudes will quickly see their circulations disintegrate.
The reasons for this are related to the way air rises and falls in circulation cells called (Hadley cells), as well as to the natural spin (related to the earth's rotation, the coriolis effect) available to air parcels at low latitudes. This natural deflection, is lowest at the equator, and highest at the poles. This deflection is what causes the clockwise rotation in the Southern Hemisphere and counterclockwise in the Northern Hemisphere. The zero point in rotation is very near the equator.
Try the links in the MadSci Library for more information on Earth Sciences.