Inaugurating the 1980 season in the western North Atlantic, Hurricane Allen -- one of the most powerful hurricanes in this century -- has given storm trackers another opportunity to show their prowess. With satellite and aircraft , they are able to follow Allen's development and give ample warning.
But they are not content with this level of success. As Neil Frank, director of the US National Hurricane Center (NHC)at Coral Gables, Fla., constantly points out, the most important part of the hurricane warning operation is public preparedness and response.
Hurricane forecasting has reached a plateau -- with no major progress in sight, Dr. Frank says. Therefore, any significant improvement in the effectiveness of the warning system depends on people making better use of the warnings.
Thus, while meteorologists at NHC are geared up for the 1980 hurricane season , their thoughts run back to that devastating duo, David and Frederic, which dramatized the importance of effective public response last year. Dr. Frank calls David, in particular, "an historic storm" for the United States because the public made such prudent use of his agency's forecasts -- not overreacting, but boarding up and moving out as necessary.
The difference between the death toll due to these storms in the US and in many parts of the Carribean underscores the point.
The storms were "multibillion-dollar hurricanes." Frederic, especially, did more than $2 billion worth of damage in the US alone, making it one of the most costly the country has experienced. Yet the "human damage" in the US was minimal, although Frederic forced temporary evacation of 200,000 to 300,000 people.There were about 25 fatalities in the US and Puerto Rico for David and around 8 for Frederic. This conv trasts with more than a thousand deaths in the Caribbean from David -- mainly in the Dominican Republic, where floods took out entire villages. Also, about 150,000 people in the Dominican Republic and 60, 000 on Dominica were left homeless.
Public awareness and response were the key factors that made the difference. In much of the Caribbean, officials received NHC warnings; but most people never got the word because communications were poor. These people were caught off guard in homes and villages that in many cases were built in water courses for flash floods.
This is no cause for complacency in the United States. Dr. Frank notes that millions of Americans living in hard-to evacuate areas along the Gulf of Mexico and Eastern Seaboard are vulnerable to hurricane- driven tides and probably could not get out in time if a warning is given. Public preparedness probably is the onlym factor that can substantially improve the effectiveness of the hurricane warning system for at least the decade of the 1980s.
He explains: "Hurricane forecasting here [at NHC] is not better today than it was 10 years ago. There may even be some evidence that it has slightly deteriorated. With the advent of satellites, we have abandoned some older, expensive observing platforms -- ships and some island stations. The main hurricane steering currents are in the low and middle levels of the atmosphere, where satellite cloud pictures don't give good wind flow indications. Aircraft are inadequate to take over the [the general wind field] sampling job. So we are losing our ability to evaluate the mid-level circulation over the ocean properly.
"I'm not opposed to cutting back on those expensive conventional observing platforms. But the message is that, in many coastal areas where we need more lead time with the most accurate forecasts -- 24 hours instead of 12 hours -- we are just not going to be able to provide it. We couldn't do it without overwarning [forcing needless and costly evacuation over an unnecessarily large area]. Radar doesn't help here; it only fine-tunes the tracking."
Also, there are limits to meteorological understanding. Even when general wind flows are known, it is unclear how a hurricane interacts with these so-called "steering" currents. So they are only a partial guide to storm motion. Indeed, it is hard to foresee the exact course of a hurricane under the best of observing conditions.
Hurricane David illustrated this point. After a straight-in run at Miami, it suddenly and unpredictably swerved up the Atlantic coast of Florida.It wandered like a wobbly top, staying just off shore until heading inland north of Palm Beach. Forecasters could not anticipate which way the storm would wobble, although radar and aircraft kept it under constant surveillance. These small oscillations, which are typical of hurricanes, remain a mystery. Yet, where a storm could come ashore at any time, such wobbles are crucial.
American hurricane meteorologists are not giving up on improving their warning system. But those responsible for this system take a realistic view of its present and foreseeable capabilities.
That, Says Dr. Frank, is why he emphasizes the role of a well-informed public assuming its share of responsibility for its own safety.