Hazards Galore (continued)

New aircrew were often dismayed by the weather conditions experienced out on missions. The main trouble, particularly in the tropics, was towering cumulus and cumulonimbus cloud, which not only obscured visibility, but made flying practically impossible. Cumulonimbus is the king of the clouds. This monster typically rose from a base of 2–3,000 feet to a height of 20,000 feet in high latitudes, and to 50,000 feet in the tropics. The typical appearance of the cloud is like a giant cauliflower, which spreads out at great heights into the well-known anvil-shaped cloud accompanying a thunderstorm. This cloud is a veritable powerhouse of energy—a mass of turbulence. Updraughts and downdraughts within the cloud have been recorded at velocities up to 200 kilometres per hour. Such violent concentrated winds produce profound effects on aircraft, driving them helplessly hither and thither, interfering with instrumentation and engine power—even disintegrating them. These giant clouds are typically associated with the localised convectional storm on a hot, humid day. More often, they herald the passage of a fast-moving cold front such as the southerly buster, well-known in Sydney. They represent the spawn of disaster to aircraft.

The above conditions are aggravated by other activities emanating from cumulonimbus clouds:— lightning, blinding rain, icing and hail are common features. My diary records a report by members of an aircraft of 521 Squadron on 18 July 1943, on one of the many tropical storms encountered:

'A terrific explosion, then a ball of blue flame ran the whole length of the aircraft and disappeared out the rear turret . . . nothing apart from the aerial in the aircraft was affected, except for damage to morale!' [36]

Bureau of Meteorology