Cyclone Savannah

Savannah's precursor tropical low located to the south of Java on 8 March

The Indonesian islands of Java and Bali were significantly affected by Savannah's precursor tropical low during the first half of March. Very heavy rainfall occurred across large parts of the islands as the tropical low tracked westwards, causing rapid river level rise, flooding and many landslides. A total of ten people died during the disaster, making Savannah the deadliest tropical cyclone in the Australian region since Tropical Cyclone Cempaka, which killed at least 41 people in Java in November 2017.[10][11][12][13]

The Indonesian Agency for Meteorology, Climatology and Geophysics indicated that 148 mm (5.8 in) of precipitation fell in parts of Yogyakarta during 17 March. The regency of Bantul, located downstream from six major rivers, as well as the neighbouring Purworejo Regency, experienced widespread flooding with depths of up to 2 m (6.6 ft). More than 5,000 residents were forced to evacuate, and access to electricity to was cut by the floodwaters. Numerous landslides in Bantul were also triggered by the extreme rainfall, causing damage and hampering rescue and evacuation efforts. One landslide in Bantul's Imogiri district destroyed two houses at the bottom of a cliff, killing three people, and leaving one more missing. Another person was later swept away by floodwaters, and another was killed when a wall collapsed.[10][14]

The economic losses that occurred in Madiun Regency were the worst in two decades, with damages and losses amounting to more than Rp54 billion (US$3.8 million), and more than 5,700 families affected by the disaster. 5,086 houses were damaged by floodwaters throughout the region, and flooding and landslides destroyed three bridges and covered many roads, impeding transportation.[1][27] A car crash occurred on a wet road in Madiun, resulting in the death of a five-year-old boy and serious injuries to two adults.[11] 497 hectares (1230 acres) of rice fields were submerged, causing crops to fail and farmers to harvest early to prevent further damage. Significant livestock losses also occurred, including cows, goats and more than 4,000 chickens.[1] In the nearby village of Klumutan, inundation of up to 5 m (16 ft) in depth damaged hundreds of houses.[28] Two residents in a village in Madiun died of illness during the event, but were unable to be buried initially due to the flooding of the local cemetery.[29]

Further damage and agricultural losses occurred in the regencies of Ngawi, Tulungagung, Bojonegoro and Ponorogo, totalling more than Rp51 billion (US$3.6 million). In Ngawi, flooding caused approximately 1,400 hectares (3,500 acres) of agricultural land to become submerged, and damages and economic losses in that regency alone reached Rp33.2 billion (US$2.35 million).[5] 1,183 hectares (2,920 acres) of agricultural land was damaged by flooding in Tulungagung, with crops of rice, melon, chili, long bean and onion affected.[3] In Bojonegoro, flooding of the Solo River resulted in widespread impacts. Inundation occurred in 48 villages, affecting more than 1,600 families and causing 50 families to evacuate. A total of 2,097 hectares (5,180 acres) of rice fields were submerged by the river water, as well as two kindergartens and three schools.[4] Even after beginning to recede, the level of the Solo River was at above 27.44 m (90.0 ft) in Karangnongko District, causing the Indonesian National Board for Disaster Management to issue red alerts for riverine flooding for areas further downstream.[30] Flooding in Ponorogo from the Solo River caused five bridges to collapse, and submerged 1,700 hectares (4,200 acres) of rice crops.[2]

Combined damage in the regencies of Magetan, Sukoharjo, Klaten and Bulelung exceeded Rp2 billion (US$140,000). In Magetan, flooding of several rivers caused significant damage to infrastructure, agricultural land and residential areas. 100 people were stranded when nearly 500 houses were flooded in two villages, and damage to roads further inhibited access to affected areas. Losses were sustained on agricultural land, and livestock were killed by the flooding.[6] 379 hectares (940 acres) of rice fields were inundates in Sukoharjo,[8] and flooding of the Gamping River in Klaten submerged 738 hectares (1,820 acres) of rice fields.[7] In Bulelung in northern Bali, heavy rainfall caused a river that was clogged with garbage and wood to overflow, damaging roads, bridges and electricity infrastructure. A government-subsidised housing complex sustained damage from the flooding, with one house being swept away by the floodwaters.[9]

Four tourists were killed and three others were injured in Magelang Regency in central Java on 13 March. The victims had been tubing along the rapids in a river when they were overcome by flash flooding.[12] Several villages in the Pasuruan Regency were affected by flooding, with roads and residential areas becoming inundated. Water levels reaching as high as 1.5 m (4.9 ft) in Kebrukan Village.[31]

The Australian territories of Christmas Island and the Cocos (Keeling) Islands experienced minor impacts as Savannah passed nearby. During 11 March, Savannah's precursor tropical low passed just to the south of Christmas Island.[19] At that time, the system had ten-minute sustained winds of only about 35 kilometres per hour (22 mph). As such, no strong winds were recorded on the island. A maximum gust of 50 kilometres per hour (31 mph) was observed at 20:05 UTC on 12 March once the system had strengthened further after moving away to the west.[32] A total of 60.2 mm (2.37 in) of rainfall was recorded on Christmas Island during the seven days from 8–14 March.[33] The system made its closest approach to the Cocos (Keeling) Islands on 14 March, after intensification into a Category 1 tropical cyclone.[17] In preparation for the system's anticipated impacts on the islands, the BOM began issuing tropical cyclone advice products for residents and local authorities at 06:50 UTC on 13 March. Strong sustained winds were experienced on the islands, peaking at gale-force, and a maximum gust of 80 kilometres per hour (50 mph) was recorded at 21:35 UTC on 13 March.[34] The wind caused defoliation and vegetation damage on the islands, as well as minor damage to property, but no injuries were reported.[17] Tropical cyclone advice publications were discontinued at 06:50 UTC on 14 March as the system tracked further away from the islands.[17] Over the ten days from 9–18 March, 62.6 mm (2.46 in) of rainfall was recorded at the Cocos (Keeling) Islands Airport on West Island, the territory's capital.[35]