A teenage boy was dramatically rescued from surging floodwaters as he clung to a tree on Friday, while others were plucked from stranded cars and homes as floods swept northeastern Australia. Authorities said there were 20 water rescue cases across central Queensland overnight and early on Friday, after the remnants of tropical cyclone Oswald dumped huge rains around the coastal city of Rockhampton. Rescues included those of a woman and two children trapped in a car isolated by flood waters, and seven people taken from two flooded homes. Authorities said a teenage boy was lucky to be alive after he was found clinging to a tree as muddy floodwaters surged around him at Frenchville, some 525 kilometres northwest of Brisbane, early on Friday. “The current was so strong it just took him away,” station officer Brett Williams told the Australian Broadcasting Corporation. The national broadcaster said the boy’s rescuer was himself swept under the waters after he transferred the teenager to waiting rescuers, but later bobbed up safely further down the swollen creek. Cyclone Oswald, now downgraded, which was about 65 nautical miles west of Mackay early Friday, has flooded rivers and dumped enough rain to isolate towns, with Rockhampton on Thursday experiencing its biggest daily downpour since 1939. “They’re saying this is not a cyclone but it’s not far off it,” Rockhampton councillor Bill Ludwig told ABC, adding that parts of the city were under water and winds were “very destructive”. A severe weather warning has been issued for parts of Queensland, with the Bureau of Meteorology saying heavy rainfall could cause flash flooding in the state’s southeast, possibly reaching areas north of Brisbane late on Friday. “Six hour rainfall accumulations of 100 to 200mm are possible,” it said. The bureau said severe flash flooding was reported overnight in the Yeppoon area, north of Rockhampton, where rainfall of 271mm has been recorded since early Thursday. The rain has left major highways closed and cut rail services. Emergency Management Queensland said authorities were on high alert. Two years ago floods in Queensland left more than 30 people dead, 29,000 homes and businesses inundated and some 2.5 million people affected.