Courses of instruction were organized. In all of them one fact became abundantly clear in the first two years. No two hurricanes are exactly alike. All of them are big compared with thunderstorms and tornadoes, but some are much larger than others. The recco crew may run into one in the uncertain stages of formation and at other times they may be nosing into an old storm with strange and unsymmetrical parts. Of certain elements they were reasonably sure—all these storms have clouds, rain, squalls, and central low pressure, with strong winds spiraling more or less regularly in a direction against the motions of the hands of a clock.
With these thoughts in mind, the instructors tried to devise methods that would prevent accidents. “What do you mean, accidents?” asked a junior weather officer at one of the conferences. “The whole thing is just one big accident, if you ask me. There’s only one rule that’s any good. Just be careful and don’t fall in the ocean!” As a matter of fact, most of the rules had that one vital thought in mind, but there were different ways of doing it.
The Air Corps and Navy soon developed their own special methods. From the beginning the Navy preferred the low-level method; that is, they flew by the quickest route to the calm center of the storm, going in at a low level, generally at an elevation between three hundred and seven hundred feet. There are good reasons for this. Weather information—especially the facts they want about tropical storms—is vital to the safe operation of surface ships such as cruisers, destroyers and mine sweepers, and it is also used in the movement of aircraft from and to the decks of carriers. Task forces want to know about the speed and direction of winds at sea level, as well as the condition of the sea when storms are imminent.
It was the aim of the Navy to keep their weather reconnaissance aircraft below the level of clouds, where the aerologist could watch the surface of the sea as much of the time as is possible within the limits of reasonably safe operation. When in a tropical storm, the aerologist guided the pilot around or into the center. Down near the water, say one hundred to three hundred feet altitude, turbulence is apt to be very bad, sometimes extremely violent. Above seven hundred feet, clouds are likely to interfere and this was extremely dangerous at that altitude in those early years because the altimeter which they used to indicate height of the aircraft by pressure of the atmosphere was sometimes badly in error in a tropical storm. If the pilot and the aerologist lost sight of the water’s surface for a few minutes, they suddenly found the aircraft about to strike the precipitous waves of a storm-lashed sea.