IGEM Report 1: 2017-18 - THE CYCLONE DEBBIE REVIEW

The Cyclone Debbie Review

In a cyclone when wind gusts get above 100 km/h, it is considered too dangerous to continue preparations. This is the time at which any evacuation movement should cease, and emergency services will no longer be able to respond to calls. The Bureau issues two products to help planners: a Tropical Cyclone Advice for planners and the public and a Storm Tide Warning for specific disaster management organisations. TheTropical Cyclone Advice and associated track map shows the location and most likely track of a cyclone, set in a “cone of uncertainty” of its possible range of movement. The Storm Tide Warning shows, for 10 locations, the time when wind gusts are expected to exceed 100km/h, and possible heights of cyclone-driven storm tides, both for the forecast track and a worst case. Storm tide heights, therefore, are very dependent on the time the cyclone crosses the coast and the corresponding state of the tide.

In Townsville, planning continued into Sunday, with the sub-group evaluating the chances of the various storm surge possibilities. They were using the Bureau’s cyclone track maps and storm tide warning information based on the SEAtide TM probabilistic modelling system. DSITI storm tide advisors provided additional graphical overviews of the SEAtide TM model results issued four Storm Tide Warnings to the government. The one issued at 5.22pm spelled out the worst case and the most likely, based on the predicted cyclone track. The earliest onset of 100km/h wind gusts was forecast at 4.00pm on Monday 27 March and a worst case storm tide of 3.8 metres above the highest high tide of the year. The more likely predictions for the forecast cyclone track was for gusts expected by 2.00am on Tuesday 28 March and a storm tide height of just below the highest tide of the year. to inform their evacuation plans. Over the afternoon the Bureau had

The three concurrent events

North Queensland

State-level operations

Central Queensland

South East Queensland

4.30am • “Approx. 4000-5000 guests/ staff on Hamilton Island, 430 guests/staff on Daydream Island and 607 guests/ staff/contractors on Hayman Island”taff/ contractors on Hayman Island” Morning (approx. 10.30am) • TC crossed over Whitsunday islands 12.40pm • TC Debbie made landfall Airlie Beach as a category 4 1.00pm • TC crossed over Proserpine as a category 3 From 3.00pm • BoM advised gale force winds to impact Ayr 10.00pm • TC crossed over Collinsville as a category 2 Bowen and Proserpine cyclone shelters transitioned to evacuation centres Early hours • System dissipated to a tropical low south west of Collinsville Townsville LDMG stood down Mackay airport reopened with restrictions 3.00pm • Whitsunday Pilotage Area reopened Commercial flights arranged from Hamilton Island to Cairns, Sydney and Bowen Whitsunday PCYC opened as evacuation centre pm • Navy evacuates 200 from Daydream Island to Airlie Beach 5.00pm • Police assist evacuation flights on Hamilton Island 9.30pm • Last 100 evacuees from Daydream Island move from Airlie Beach to Townsville Late evening • Private charter takes Hayman Island guests to Sydney via Hamilton Island

28 March

29 March

BoM cyclone track map issued at 7.49pm on 26 March

Source: Bureau of Meteorology

30 March

31 March Burdekin LDMG stood down 3 April

Whitsunday LDMG transitioned to recovery

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4 THE THREE CONCURRENT EVENTS

North Queensland: Getting ready • Townsville