Australia: TC Ilsa tracking southeastward across Western Australia as of early April 14 following landfall over Kimberley-Pilbara coast late April 13 /update 6

Event

Tropical Cyclone Ilsa is tracking southeastward across Western Australia early April 14 after making landfall over the Kimberley-Pilbara coast as a Category 5 storm late April 13. As of 05:00 AWST, the storm's center of circulation was approximately 632 km (392 miles) east-northeast of Learmonth, Western Australia. Forecast models indicate that the storm will continue to track east-southeastward across central Western Australia while weakening into a Category 1 tropical cyclone through early April 14. The storm will then weaken further as it tracks east then northeastward across southern Northern Territory through early April 16 before turning to track north-northeast and dissipating over far northwestern Queensland early April 17. Some uncertainty remains in the track and intensity forecast; changes could occur in the coming days.

As of early April 14, the Australian Bureau of Meteorology (BOM) has issued cyclone warnings for inland areas of the eastern Pilbara, east of Marble Bar, and areas over the North Interior, including Kiwirrkurra, Kunawarritji, and Parnngurr, but not including Marble Bar and Nullagine. Emergency WA has issued a red cyclone alert for residents south of Wallal Downs, including Wallal Downs, to De Grey, Marble Bar, Nullagine, and Telfer. A yellow cyclone alert is in place for residents inland south of Nullagine, not including Nullagine, extending inland past Parnngurr, Kunawarritji, and Kiwirrkurra in the Pilbara..

The very destructive core of Ilsa, with gusts of up to 195 kph (121 mph), is impacting areas near the system center to the east of Marble Bar as it tracks inland. Destructive winds with gusts up to 155 kph (96 mph) are occurring over inland areas of the eastern Pilbara between Marble Bar and Telfer, not including Marble Bar; destructive winds are forecast to extend further inland to Telfer the morning of April 14 and extend east towards Kunawarritji the afternoon of April 14. Damaging winds with gusts to 90 kph (56 mph) are occurring over inland areas of the eastern Pilbara between Marble Bar and Telfer, but not including Marble Bar, and will extend further inland to Telfer the morning of April 14, to Parnngurr the afternoon of April 14, and to Kunawarritji and Kiwirrkurra the evening of April 14. Heavy to intense rainfall are likely in the path of the storm; 15-20 cm (6-8 inches) of rainfall is possible, with the rainfall decreasing as it tracks inland.

The following warnings are in place:

• Severe weather warning for damaging winds and heavy rainfall: parts of Lasseter, Simpson, Tanami, and Barkly districts in Northern Territory

• Severe thunderstorm warning for damaging winds: parts of Kimberley, Pilbara, and North Interior districts in Western Australia

• Flood warning: De Grey River Catchment and Sandy Desert

• Flood watch: catchments in the west Kimberley and Western Desert and in Salt Lake and Warburton districts in Western Australia as well as western inland Northern Territory

Authorities have shipped in food and fuel to last Bidyadanga, Western Australia's largest remote Aboriginal community, for seven days. Several residents requiring medical treatment have been evacuated to Broome. A large number of people in Broome remain homeless following the catastrophic flooding in January; a lack of shelter is likely to exacerbate Ilsa's impact. Multiple communities in the northwestern region of Western Australia, including Bidyadanga, Eighty Mile, Punmu, Telfar, and Wallal Downs. Holidaymakers and people traveling in caravans between Port Hedland and Broome were pre-emptively evacuated. Evacuation shelters are located at JD Hardie Centre, Marble Bar Civic Centre, Newman Recreation Centre, and Nullagine Primary School. Further evacuations are likely across other communities.

Authorities are clearing boats from all berths in the inner harbor of the Port Hedland Port, including iron ore carriers. Roadhouses along the Great Northern Highway are closed, including in Pardoo. The Great Northern Highway between Roebuck Roadhouse to Pippingarra Road, Port Hedland, as well as several other smaller roads, are closed. Authorities have warned that the North West Coastal Highway could be closed between Port Hedland and Broome due to flooding.

Early reports indicate significant damage at Pardoo Roadhouse and Tavern. Officials have not yet conducted any damage assessments due to the dangerous conditions; the full extent of the damage from Ilsa is likely to be known over the coming hours and days.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible.

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a severe health threat.

Advice

Activate contingency plans in areas where officials forecast tropical cyclone conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

Joint Typhoon Warning Center
Australian Bureau of Meteorology
Emergency WA