FIGURE 12 Wind-wave patterns from a hurricane.13

start recurving. His luck holds; the storm veers slightly to the southwest and he makes port the next day. (See Figure 12.)

By then the hurricane pressure has dropped to 940 millibars, hurricane force winds extend 50 nautical miles in all directions, and seas of up to 40 feet are reported. In two days, gales extend out 200 nautical miles and hurricane force winds out to 75 nautical miles. At this point, the storm has its widest impact; it is recurving north, reaching colder waters and cold air aloft; the winds slowly dissipate and after a few more days the storm dies.

Today, through the use of instrumented sea buoys, airplane flights into hurricanes, satellites, and improved modeling techniques, much more is known about hurricane-generated waves. Measurements typically use an elevation of 33 feet above sea level as a reference point. The data indicate that from this elevation up to, say, 300 feet, the wind speed increases gradually, leveling out at perhaps a 25 percent increase in value. From measurements on various hurricanes, it is known that wind gusts can be around 25 percent greater than the mean wind speed. Thus, at sustained hurricane wind speeds of 64 knots, gusts to 80 knots can be expected. The state of the sea can rise rapidly, even when the eye



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