Savannah underwent rapid intensification and reached peak intensity on 17 March as a Category 4 severe tropical cyclone on the Australian scale.

[nb 2] During early March, a moderate strength pulse of the Madden–Julian oscillation tracked eastwards across the tropical Indian Ocean and into the Maritime Continent.

[16] Located south of Bali, Indonesia, and approximately 970 km (600 mi) east of Christmas Island, the nascent tropical low began moving slowly westwards.

[17][18] Tracking roughly parallel to the southern coastline of Java, the system passed just to the south of Christmas Island at 06:00 UTC on 11 March, before turning to the northwest.

The BOM upgraded the system to a Category 1 tropical cyclone on the Australian scale at 18:00 UTC on 13 March as it was approaching the Cocos (Keeling) Islands, and gave it the name Savannah.

[17][19] Six hours later, the United States' Joint Typhoon Warning Center (JTWC) indicated that the system had reached tropical storm strength on the Saffir-Simpson hurricane wind scale.

[20] Intensification continued as Savannah passed approximately 110 km (68 mi) to the west of the Cocos (Keeling) Islands, and the system reached Category 2 late on 14 March.

[17][19] Savannah became a Category 3 severe tropical cyclone the following day, and adopted a track to the west-southwest under the influence of a high-pressure ridge in the mid-troposphere further to the south.

By 00:00 UTC on 18 March, the system tracked over the 90th meridian east and into the South-West Indian Ocean cyclone region, and hence responsibility for the storm transitioned to Météo-France (MFR) at La Réunion.

[22] Immediately upon entering the region, increasing westerly vertical wind shear allowed dry air to become entrained in the storm's circulation.

[23] The system's deep convection proceeded to unravel, leaving the low-level circulation centre exposed, and ten-minute sustained winds decreased to 75 kilometres per hour (47 mph) by 00:00 UTC on 19 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.

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.

[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.

[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.

[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.

[35] Following the significant damage caused by the weather system, the Ponorogo Regency government committed to conduct dredging operations to widen the Solo River in order to mitigate future flooding impacts.