1994 Queens’s Birthday Storm
This South Pacific storm formed between 1st and 4th June 1994, and while not unusual, it affected a large number of yachts on route between New Zealand and Tonga and led to New Zealand’s largest air/sea rescue operation. Six yachts were abandoned and their crews picked up and one with its crew of three was lost.
This was not the cyclone season and the storm that developed was never officially named as such. In any case it had no core of central warm air characteristic of cyclones and hardly reached gale force winds while it was in the tropics.
None the less, its effects in the subtropics were devastating.
On June 2nd, a slight kink in the isobars of the synoptic chart near Vanuatu was the only indicator of what was about to take place.
The low pressure system developed and started to move south. Of particular significance is the area of high pressure over New Zealand that brought in a supply of cold, low level air from the Antarctic. Cold air does not mix easily with warm and the effect of this inflow was to force the existing warm air upwards. An upper level system was active and withdrew rising air faster than the incoming cold stream was able to replace it. Barometric pressure of the surface was reduced still further as the system increased in size.
This phenomenon of cold air being drawn into a deepening low pressure system is sometimes known as meteorological ‘bomb’