Two powerful storms – Cyclone ‘Senyar’ and ‘Ditwah’ – have carved a trail of devastation across the Indian Ocean region, leaving more than 1,000 people dead and tens of thousands displaced, hitting Indonesia, Thailand and Sri Lanka the most and also led to fatalities in India’s southern coast.
It was a deep depression over the Strait of Malacca first that turned into Cyclone Senyar last week and now stands dissipated over the South China Sea, according to the Hong Kong Observatory, cited in a Bloomberg report. Immediately after Senyar weakened, another cyclonic storm – Cyclone Ditwah – brewed over southwest Bay of Bengal, heading towards Sri Lanka and India.

The Senyar cyclone posed no major threat to India as it build over the Strait of Malacca – connecting the Andaman Sea of the northeastern Indian Ocean and the South China Sea of the western Pacific Ocean – and moved away from the Indian coast and towards Indonesia as well as Malaysia.
Cyclone Ditwah formed on November 27 and was headed to reach the Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coast by November 30 but stopped short of hitting the Indian coasts, however, brought heavy rainfall in the regions.
What ‘rare’ Cyclone Senyar did
In Indonesia’s Sumatra island, a week of torrential rains intensified by a “rare” cyclone Senyar has left at least 500 people dead. The death toll from floods and landslides in Indonesia rose to 502 with 508 missing, AFP news agency reported, citing a tally published by the national disaster agency showed Monday.

Rescue and relief efforts in Indonesia were hit by cut-off roads and downed communication networks, the head of country’s National Disaster Mitigation Agency, Suharyanto, said in a briefing on Sunday, the Jakarta Post reported.
The storm left an extensive damage to infrastructure damage in Indonesia, cutting off access to several villages and prompting authorities to deploy helicopters as well as navy ships to transport supplies after the storm-brought flooding that residents described as the “worst in our lifetime,” Bloomberg reported, adding that residences were submerged up to their rooftops.
The Indonesian government has also carried out aerial cloud seeding operations in an attempt to reduce rainfall over areas that were affected the most, the national weather bureau said in a statement.
Cyclone Senyar was the first tropical cyclone to form in the Strait of Malacca since the destructive Typhoon Vamei made passage there in 2001, according to the HKO.

Tropical cyclones rarely form this close to the equator, in part because of a weaker rotational force, known as the Coriolis effect, at low latitudes, the Bloomberg report mentioned.
The HKO attributed the formation of Senyar to a combination of factors – including warm water temperatures in the Strait of Malacca.
Elsewhere, Petron Malaysia Refining & Marketing Bhd halted operations at a crude oil refinery following damage from storm Senyar, the company said in a filing.
Cyclone Senyar also left Thailand devastated as flooding triggered by the torrential rains in southern part of the country claimed at least 176 lives and affected more than 20 lakh households, according to officials, cited in the report.
Total losses reportedly amount to 23.6 billion baht ($734 million or roughly ₹6,560 crore), with hotels and restaurants among the hardest hit, as per Krungsri Research. Rubber and palm oil production were also left damaged.
Cyclone Ditwah
In Sri Lanka, deaths from heavy flooding that Cyclone Ditwah brought rose sharply on Sunday, almost doubling to 334 dead. About 370 were missing.
Cyclone Ditwah, which came ashore in the island nation on Friday, led to red alert for north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts by the India Meteorological Department (IMD) for extremely heavy rain over the weekend. There was no major rain warning for Monday.
While three people have died in rain-related incidents triggered by cyclone Ditwah in Tamil Nadu over the last 24 hours, according to state revenue and disaster management minister KKSSR Ramachandran said on Sunday, the storm’s passage left Sri Lanka facing its “largest and most challenging natural disaster,” President Anura Kumara Dissanayake said in a national address Sunday night.

In Sri Lanka, fatalities from heavy flooding rose sharply on Sunday, almost doubling to 334 dead and another 370 missing. Cyclone Ditwah, which came ashore in the island nation on Friday, is forecast to bring heavy rains to some parts of southern India on Monday, according to forecasts.

The storm’s passage has left Sri Lanka facing its “largest and most challenging natural disaster,” President Anura Kumara Dissanayake said in a national address Sunday night.
Storm Koto
A third storm – Typhoon Koto – is expected to remain offshore to the east of Vietnam, slowly losing strength over the coming days. However, it is still likely to bring additional rainfall to central and north-central parts of the country, which have already suffered severe storms and historic flooding that caused at least $3 billion in damage in recent weeks.
Forecasters say rainfall should return to typical seasonal levels across most affected regions by midweek. A drier pattern is also anticipated for Peninsular Malaysia and Sumatra around mid-December, according to the latest outlook.