Volcanoes 101 . Site map . A tour through the Northeast this week will remind residents they are vulnerable to the great storms. While many factors control the number of hurricanes in a given season, Bill Gray has said the long-term trend is ruled by a conveyor belt of sorts that moves Atlantic ocean water northward from near the Caribbean to an area east of Greenland. There, the current sinks deep, moves southward and flows into the southern Atlantic Ocean and beyond.
Recent measurements show that the water in the conveyor belt contains more salt than normal.
This increases the water's density, researchers explain, causing it to sink to greater depths. This in turn increases the flow of deep water southward, which forces an increase in the flow of warm, tropical surface water northward. Thus, the northern Atlantic becomes warmer than normal, providing the heat needed to turn hurricanes into powerful killers. The answer, as best as the experts can figure, is sooner or later, or maybe never. Miles Lawrence, a hurricane specialist at the National Hurricane Center, says there's nothing unusual about the Atlantic hurricane season so far.