On 2 April 2005 a density current formed along a pre-frontal trough and progressed eastwards across South Australia. Record high April temperatures were experienced ahead of the trough, with severe wind gusts recorded across many parts of the State as winds shifted from northwesterly to southwesterly. An extensive area of dust accompanied the density current, producing significant reductions in visibility in its wake. One minute data from the Royal Australian Air Force (RAAF) Base Edinburgh were used to examine the properties of the density current including its height, propagation speed, temperature profile and effect on wind speed. A periodicity in the wind, pressure and visibility was observed, varying according to the Brunt-Väisälä frequency. These oscillations were indicative of internal gravity waves at the head of the density current propagating in the opposite direction to the surface wind.
B. Gibson (Sat,) studied this question.