Cyclone Seroja triggered flash flooding and massive landslides in southeastern Indonesia and Timor-Leste
Cyclone Seroja triggered flash flooding and massive landslides in southeastern Indonesia and Timor-Leste between April 3-5, resulting in at least 272 fatalities. More than 71,000 homes and other structures sustained damage in Indonesia alone. Total economic cost was estimated at $475m.
The storm made landfall in Western Australia on April 11. Official estimates suggested potential reconstruction costs of up to A$200m, while the Insurance Council declared a catastrophe.
In the US, an active month of severe weather resulted in multiple thunderstorm outbreaks. The outbreaks, which were driven by large hail, tornadoes and damaging straight-line winds, left considerable damage to residential and commercial property, automobiles, and agriculture in parts of the Plains, Midwest, Southeast and Northeast.
The most significant outbreak occurred from April 27-30, where a particularly damaging sequence of hailstorms affected three heavily populated areas on April 28. Hail larger than the size of baseballs impacted the San Antonio (TX), Fort Worth (TX), and Norman (OK) metro regions and caused extensive damage. Total economic losses from these three areas alone are expected to well exceed $1 billion.
For the entire month of April, the US insurance industry is expected to face a multi-billion-dollar bill for thunderstorm-related claims payouts.
Elsewhere, western and central regions of Europe experienced a significant cold spell within the first week of April as numerous locations recorded record lows for the month, with temperatures well below freezing.
Late spring frost caused significant damage to viticulture, fruit trees and other vegetation. Preliminary estimates suggest an economic impact of more than €5 billion, most notably in France and Italy.
Steve Bowen, managing director and head of Catastrophe Insight on the Impact Forecasting team at Aon, said: “Public perception often assumes that tornadoes drive the bulk of annual severe convective storm (SCS) damage costs. The reality is that large hail typically accounts for a majority of thunderstorm-related losses in North America during any given year.
”April 2021 was a case in point – the month featured the lowest number of US tornadoes for April since 1992, yet a multi-billion-dollar damage bill is anticipated following extensive hail impacting highly populated areas of Texas and Oklahoma. As more population moves into high-risk areas for the SCS peril, it is anticipated that costs associated with hail will only grow in the future.”