Hurricane forecast: more action than usual likely this year

THIS year's North Atlantic hurricane season, which began June 1, will probably be more active than average and much more active than 1986 or '87. So warns hurricane forecaster William M. Gray of Colorado State University. People living along the Atlantic and Gulf Coasts of North America and in the Caribbean Basin should take this warning seriously.

Gray's seasonal forecast, which he updates Aug. 1, has foretold the last several hurricane seasons fairly accurately. His system is not just informed guesswork. It's based on a predictive equation that takes account of the main meteorological factors that appear to govern North Atlantic hurricane action.

The US Federal Emergency Management Agency is urging officials in all communities potentially exposed to hurricanes to tighten up their contingency planning. In a recent statement, the agency notes that more than 63 million people now live within 50 miles of the sea along the East Coast alone.

Agency director Julius W. Becton Jr. shares the concern expressed by US National Weather Service officials, that lack of hurricane experience may lull many coastal residents into a false sense of safety. ``Eighty percent of these people have never experienced the direct impact of a hurricane, and their numbers are increasing three times faster than the [United States] national population,'' he says.

The agency reports that improved warning systems, advanced preparation for emergency evacuation, and other contingency planning have reduced deaths and damage in many communities when hurricanes have struck. With the rapid development of coastal areas, however, the agency urges all communities at risk to rethink their hurricane planning.

In his 1988 forecast, Gray predicts seven full-grown hurricanes and four tropical storms intensive enough to be given a name. He also expects 30 hurricane days. A ``hurricane day'' is a part of any day when a tropical storm has winds of hurricane intensity - that is, winds greater than 73 miles an hour.

Thus the forecast calls for one more hurricane and five more hurricane days than the 40-year average. Such an active season would contrast dramatically with last year, which experienced only three hurricanes, four tropical storms, and seven hurricane days. In fact, 1988 would be the most active since 1981 except for 1985, which also had seven hurricanes and 29 hurricane days.

Gray makes the point that modern coastal development has occurred during a period of relaxed hurricane violence. He assesses this partly by means of a Hurricane Destruction Potential index based on sustained maximum wind speeds in a season's storms. He notes that this index was substantially higher from 1947 to 1969 than it has been since that period.

Gray cannot foretell when and where individual storms will develop or where they will go. But his record on foretelling the overall activity of a hurricane season is excellent. This is indeed a season for all communities with hurricane risk to review their preparedness.

A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.