BAMOS
Jun 2018
Synoptic weather chart for 5th
February 1938.
Image: The Sydney Morning Herald,
Monday 7th February 1938
time, and was working for a beach inspector hiring out “surf-
o-planes” to swimmers—these are inflatable rubber mats that
can be used as flotation devices in the surf. In the Central Coast
Express Advocate article he recalled: The impact of the 1938 low-pressure cell was noted in a 2015
article in the Daily Telegraph “Black Sunday 1938: Hundreds
washed out to sea on Bondi Beach as freak waves kill 5, injure
dozens”. 3
“It wasn’t a wave, it was just a slow rising of the water. It came
across, it was like the beach was now, it came over the rise and
people were screaming and picking their clothes up, no panic, it
was just because they were getting wet. We just put the surf-o-
planes up in the surf club out of the way. It just kept going and
going and when it got to a foot or 18-inches deep it just receded
and what happened was because the people were in the water,
when that volume came out, it carried them out to sea.” “On that weekend the weather was clear but a large swell was
hitting the coast. On Saturday, lifesavers on patrol at Bondi had
been busy pulling people from the heavy surf. They had even
notched up a record of 74 rescues in one hour.”
4. The meteorological situation
Attempts to find the synoptic weather chart for Sunday 6th
February were unsuccessful. However a synoptic chart for the
5th February was printed in the Sydney Morning Herald on the
following Monday (image above).
The chart shows a low pressure cell off the south coast of NSW
and the accompanying Ocean Forecast (for Sunday 6th) stated:
“Fresh to strong south-westerly to south-easterly winds, and
moderate to rough seas, are expected over most of the Tasman Sea
and around the south-eastern corner of the continent.”
From this chart it seems that the central pressure of the low was
close to 29 inches of mercury and this corresponds to around
982 hPa. A low-pressure cell of this central pressure at this
latitude could well generate winds of 50–70 km/hr, and this in
turn could produce significant swell waves (3 to 4 metres) along
the NSW coast—as indicated on the forecast.
5. The seismological situation.
A list of 1938 earthquakes can be found on Wikipedia. 4
Two earthquakes of magnitude 7.0 or more occurred in early
February in areas that could have resulted in Australian
tsunamis.
a. A magnitude 8.5 earthquake struck the eastern Banda Sea,
near Indonesia, on 1st February.
b. A magnitude 7.0 earthquake struck the Quindio
Department, Colombia on 5th February.
However analysis of these two events leads to the conclusion
that a Sydney-area tsunami was unlikely from either. The Banda
Sea earthquake would not significantly impact on the east
coast, while the timing of the Colombian event does not fit with
a 3 pm arrival in Bondi. In addition there was no corroborating
evidence (reports) of a tsunami occurring elsewhere on the
Australian mainland or in the Pacific that could be attributed to
either of these earthquakes.
However Geoscience Australia raises the possibility of a localised
tsunami along the NSW coast from a ”submarine slump” 5 within
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