Tropical cyclone ITA made landfall in northeastern Australia on 11 April 2014 Dr. Susanne Haeseler; updated: 17 April 2014 Introduction In Australia, the severe tropical cyclone ITA made landfall near Cape Flattery in northeastern Queensland on 11 April 2014 at about 10 p.m. (12 UTC) (Fig. 1 and 2). Just before, it reached its highest intensity, category 5 on the 5-stage Australian tropical cyclone category system. Cyclones of this strength are very rare in Queensland at the end of the cyclone sea- son in April. Fig. 1: Satellite image on 11 April 2014, 06 UTC. Cyclone ITA is situated off Australia’s northeastern coast. [Source: DWD] 1 Cyclone ITA evolved from a tropical low that was situated southwest of the Solomon Islands in the Coral Sea on 5 April (Fig. 2). It moved westward to Queensland, then southward along the coast, later to the southeast, and back to the Pacific. Hurricane force winds damaged buildings and uprooted trees. Several towns were temporarily cut off as heavy precipitation caused flooding. Fig. 2: Track of tropical cyclone ITA over the Coral Sea and northeastern Australia in April 2014. The Solomon Islands with their capital Honiara are shown in the upper right of the map. The intensity of the tropical cyclone (numbers in the symbols for the cyclone) refers to the 5-stage Australian tropical cyclone category system. [Source: BoM] Wind and precipitation in the range of ITA Already at the beginning of its development as a tropical low in early April, ITA caused heavy rains on the Solomon Islands, an archipelago in the South Pacific northeast of Australia. A river burst its bank leading to floods that claimed many victims. Cyclone ITA reached its highest intensity off the Australian coast. In the early evening of 11 April, the centre of ITA crossed Lizard Island, an island northwest of Cape Flattery. This crossing is indicated by the sharp drop in the wind velocity, which is typical for the centre of tropical cyclones (Fig. 3). Before and after this calm, maximum wind speeds of hurricane force (118 km/h and more) up to 158 km/h were recorded around the cyclone centre. The air pressure dropped to 954 hPa. Nobody was injured on the island because it was evacuated in time due to the cyclone warnings, but there was considerable damage to the vegetation. 2 Fig. 3: Air pressure (in hPa; top) and maximum wind speed per 10 minutes (in km/h; bottom) at Lizard Island on 11 April 2014. Time data is given in local time. GMT = UTC. [Source: AIMS] Then cyclone ITA made landfall near Cape Flattery. On 11 April 2014 between 8 and 9 p.m. (10 and 11 UTC), wind gusts of nearly 160 km/h and 10-minute sustained winds of more than 100 km/h were recorded at Cape Flattery. More than 70 mm of rain fell within 12 hours. From 12 to 15 April, no data was available from that site, probably due to damage caused by the cyclone. ITA caused torrential rains along the eastern coast of Queensland. Between Cape Melville (approx. 125 km northwest of Cape Flattery) and Townsville (see Fig. 2), 24-hour precipita- tion totals of 100 to 300 mm were recorded, even more locally (Fig. 4). At Bowen a flash flood occurred when 110 mm of rain fell within one hour. During the crossing of cyclone ITA the following maximum values for wind gusts and 24-hour precipitation totals (measured at 9 a.m. local time) were recorded at sites along the eastern coast of Queensland: station wind gusts 24-hour precipitation Cooktown 122 km/h 161 mm Cairns 63 km/h 99 mm Innisfail 101 mm Cardwell 307 mm Townsville 93 km/h 177 mm Bowen 149 mm 3 Fig. 4: Precipitation totals (in mm) for Queensland on 12 April 2014 (top) and on 13 April 2014 (bottom). The data refer to the 24-hour periods before 9 a.m. of the day. [Source: BoM] 4 The occurrence of tropical cyclones in Queensland Tropical cyclones predominantly occur in northern Australia, where one precondition for their formation, sea surface temperatures of at least 26.5 °C, is more likely than farther south. Most cyclones in the Queensland region form from lows within the monsoon trough between November and April, the official cyclone season in Australia. In the sea areas around Queensland, the area of responsibility of the Tropical Cyclone Warn- ing Centre (TCWC) Brisbane, an average of 4 to 5 tropical cyclones occur per year. Cyclone ITA was unusual in several respects: first, because of its high intensity while cross- ing the mainland, and second, the occurrence of such a strong cyclone at the end of the cy- clone season in April. Also the cyclone track of ITA was unusual, because tropical cyclones rarely cross the south of Queensland. The last severe tropical cyclone of a similar strength as ITA that crossed Queensland was cyclone YASI in February 2011. Prior to that, two severe tropical cyclones hit Queensland in 2006: LARRY in March and MONICA in April. But opposite to ITA, the cyclones LARRY, MONICA and YASI moved west to the interior of Queensland. Sources and further information . Australian Government, Bureau of Meteorology (BoM) http://www.bom.gov.au/ . Australian Government, Bureau of Meteorology (BoM): Climate Data Online. http://www.bom.gov.au/climate/data/ . Australian Government, Bureau of Meteorology (BoM): Frequently Asked Questions. http://www.bom.gov.au/cyclone/faq/index.shtml . Australian Government, Bureau of Meteorology (BoM): Severe Tropical Cyclone Ita. Queensland Regional Office. http://www.bom.gov.au/announcements/sevwx/qld/qldtc20140405.shtml . Australian Government, Bureau of Meteorology (BoM): Severe tropical cyclone Ita to im- pact far north Queensland coast. Media Release, 11 April 2014. http://www.bom.gov.au/announcements/media_releases/ho/20140411.shtml . Australian Government, Bureau of Meteorology (BoM): Tropical Cyclone Intensity and Im- pact. http://www.bom.gov.au/cyclone/about/intensity.shtml . Australian Government, Bureau of Meteorology (BoM): Tropical cyclones. http://www.bom.gov.au/jsp/ncc/climate_averages/tropical-cyclones/index.jsp . Australian Government, Bureau of Meteorology (BoM): Tropical Cyclones in Queensland. http://www.bom.gov.au/cyclone/about/eastern.shtml . Australian Government, Bureau of Meteorology (BoM): Tropical Cyclone Trends. http://www.bom.gov.au/cyclone/climatology/trends.shtml . Australian Government, Bureau of Meteorology (BoM): Tropical Cyclone Warning Services. http://www.bom.gov.au/cyclone/about/warnings/index.shtml . Australian Institute of Marine Science (AIMS): http://www.aims.gov.au/ . Couriermail News (April 13, 2014): Tropical Cyclone Ita crosses Queensland coast north of Cooktown and threatens flooding rains down coast. http://www.couriermail.com.au/news/queensland/tropical-cyclone-ita-crosses-queensland- coast-north-of-cooktown-and-threatens-flooding-rains-down-coast/story-fnkt21jb- 1226880411248 . Department of Community Safety, Queensland: UPDATE: Tropical Cyclone Ita severe weather – Sunday 13, April 2014. http://www.emergency.qld.gov.au/news/view.asp?id=10745 5 . Department of Community Safety, Queensland: UPDATE: Tropical Cyclone Ita severe weather – Monday 14, April 2014. http://www.emergency.qld.gov.au/news/view.asp?id=10751 . Deutscher Wetterdienst (DWD) www.dwd.de . Lizard Island Resort: Cyclone ITA Update. http://www.lizardisland.com.au/2695.aspx . news.com.au (April 11, 2014): Ita is breaking the rules: Why is there a cyclone so late in the year? http://www.news.com.au/technology/environment/ita-is-breaking-the-rules-why-is-there-a- cyclone-so-late-in-the-year/story-e6frflp0-1226881204389 . news.com.au (April 13, 2014): She lost her blow but dumped a load: far North Queensland swamped with floods as Cyclone Ita heads south of Cairns. http://www.news.com.au/national/she-lost-her-blow-but-dumped-a-load-far-north- queensland-swamped-with-floods-as-cyclone-ita-heads-south-of-cairns/story-fncynjr2- 1226879482288 . ReliefWeb: Solomon Islands: Flash Floods – April 2014. http://reliefweb.int/disaster/fl-2014-000045-slb . UNISYS: 2014 Hurricane/Tropical Data for Southern Pacific. http://weather.unisys.com/hurricane/s_pacific/2014/index.php 6 .