Charts of the Past with Blair Trewin
BAMOS April 2021
25
22 February 1929
The late 1920s and early 1930s were a very dry period in many parts of inland Australia . Until it was surpassed in 2019 , 1929 was the driest year on record for South Australia ( and 1928 the third-driest ). Much of western Queensland had ten consecutive years of below-average rainfall .
It was a different story on the east coast , much of which experienced a wet summer in 1928−29 . The most significant event was in late February . A tropical cyclone developed off the Queensland coast on the 19th and moved southeast and then east over the next few days . While the cyclone is believed to have been relatively weak ( the minimum central pressure recorded was 996 hPa , although cyclone intensity was often underestimated in the pre-satellite era ), and its closest approach to the coast was about 150 km northeast of Mackay , moist easterlies south of the system fed into an inland trough to produce extreme rainfall on parts of the coast .
The heavy rains began on the 19th , centred on the region between Bundaberg and Gladstone , with numerous falls over 100 mm in the 24 hours to 9am on the 20th , including 181.4 mm at Miriam Vale . The next day , the focus of the heaviest rains moved into the Rockhampton area , where they remained for three days . 388.6 mm fell at Rockhampton on the 21st , 233.2 mm on the 22nd and 174.0 mm on the 23rd . The three-day total of 795.8 mm was easily the highest on record ( the next highest was 569.7 mm in February 1888 ), whilst the daily total on the 21st was also the highest on record . A number of other sites close to Rockhampton also exceeded 700 mm over the three days , including Glenlands ( 871.0 ), Kabra ( 770.8 ), Gracemere ( 752.2 ) and Byfield ( 748.5 ). 507.5 mm at Glenlands on the 21st was the highest daily total of the event . The rain was relatively localised ; four-day totals over 100 mm were largely confined to the coastal strip between Mackay and Bundaberg , with only limited extension inland , and the most extreme totals almost all occurred within 50 km of Rockhampton .
There was significant local flooding around Rockhampton , as well as severe damage in Monto . Substantial crop damage and road washaways were reported , and there were two deaths ; at Rockhampton and Gracemere . The extent of main river flooding was limited as the rain did not extend to the inland parts of the catchment to the same extent as in other flood events , and there were only limited reports of building inundation . The
Fitzroy River peaked at 7.6 m , just above the moderate flood level , and about 2.5 m below the 1918 record peak ( and 1.5 m below 2011 ).
The monthly total of 923.9 mm was a record for Rockhampton for any month in 150 years of data . It was also a very wet February along most of the New South Wales coast , with several Mid-North Coast sites exceeding 1000 mm for the month . Some of the records set around Port Macquarie in early February were not approached until the March 2021 event ( see report earlier in this issue on page 7 ).
The 22nd also marked the end of a prolonged period of warm , humid weather in south-eastern Australia as a trough moved across Victoria . There had been six consecutive days at Melbourne between 30 ° C and 34 ° C from the 16th to the 21st , which ended with severe thunderstorms on the evening of the 21st . 12 mm fell in eight minutes with 45.5 mm in total , with significant flash flooding and one death from electrocution . Numerous other totals around 50 mm in thunderstorms were reported on the 21st and 22nd in central and western Victoria , and in central New South Wales .
It was a month of persistent heat and humidity , particularly in western Victoria and eastern South Australia . Nhill had its thirdhottest February without once reaching 40 ° C , while Adelaide had 21 days over 30 ° C for the month , a February record and the highest percentage observed in any month .
Synoptic chart for 0900 AEST , 22 February 1929 .