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J The hurricane's main source of strength is provided by warm and moist air-amply supplied by a tropical ocean environment, where the water temperature is usually hotter than 79' F. Evidence suggests that heat energy-released as warm, moist air is pumped up the vertical circulation system hy low altitude winds and sucked out the top by higher level winds (much like smoke is drawn out of a chimney on a gusty day, fanning the flames below)-is the primary driving force of the storm. The most intense winds are at the lower altitudes. The energy released by a hurricane in one day, if converted to electricity, would supply U.S. power needs for some six months. Many hurricanes wallow in their region of origin, but about two per season-lured by the westward wafting tradewinds of the tropics and coaxed by their own wind patterns-venture during summer and fall vacationtime on a haphazard north- easterly course to the U.S. Gulf and Mlantic Coasts. While in the tropics, the hurricane ambles sluggishly forward at 15 m.p.h. or less. Its speed quickens as it moves north, some- times exceeding 50 m.p.h. And it increases in size and intensity until an area 2S to more than 400 miles wide is blanketed by circular winds whirling 40 to more than 150 m.p.h. As the storm sweeps over the U.S. mainland, it encounters a hostile environment-far different from its brewing grounds several hundred miles to the south. Slowed by friclion with land, choked by cooler, drier breezes and starved by the lack of tropical marine air needed for sustenance-the hurricane even- tually dies. But not without marring the landscape with its death-throe flails. In the last 50 years, hurricanes have taken almost 5,000 lives and several hundred million dollars in property losses. Hurricane winds fling pieces of buildings through the air like shrapnel, topple trees, tip over mobile homes, knock over trains, cast boats ashore, crumple cars and drive lake waters into populated areas. Hurricane Celia did $454 million damage in 1970, of which $310 million was insured-much of it caused by a gust of wind lasting less than 30 seconds. 26 But drowning from flood-producing rain and wind-driven ocean surges causes more than 7S per cent of hurricane deaths. The typical hurricane dumps six to 12 inches of rain. The resultant flash flooding may continue to cause loss of life and property long after the winds subside. Wind-driven tides '10 to 20 feet above normal have sunk ships, inundated islands, eroded coasllines, forced ocean water 25 miles inland, destroyed crops and washed out roads and bridges. Most of the 6,000 deaths in the Galveston Ilurricane of 1900 were caused by slorm tides. Hurricane Camille, the greatest U.S. storm prior to Agnes, hrought 27 inches of rain and 24-foot tides in 1969, killing 256 Americans and causing damages of $1.4 billion.