US hailstorms and tornadoes dominated natural catastrophe costs in the first half, but global losses were less than half average levels, according to separate reports by Munich Re and Impact Forecasting.

Overall losses totalled $US41 billion ($52.5 billion), down from $US111 billion ($142 billion) in the corresponding period last year and compared with a 10-year average of $US102 billion ($130.6 billion), Munich Re estimates.

Insured losses totalled $US19.5 billion ($25 billion), down from $US32 billion ($41 billion) in the corresponding half last year and an average of $US29 billion ($37 billion).

Aon Benfield subsidiary Impact Forecasting estimates first-half economic losses were $US53 billion ($67 billion), 56% down on the 10-year average and 39% below the 17-year average.

Insurance losses were estimated at $US22 billion ($27 billion), 35% below the 10-year average.

“The financial toll from natural catastrophe events during the first six months may not have been historic, but it was enough to lead to challenges for governments and the insurance industry around the world,” Impact Meteorologist Steve Bowen said. “This was especially true in the US after the insurance industry faced its second-costliest first half on record following a relentless six months of hail-driven severe weather damage.”

Munich Re says US storms accounted for three of the five costliest events in the half, each causing economic losses above $US2 billion ($2.6 billion). The combined total reached $US18.5 billion ($23.7 billion), of which $US13.5 billion ($17.3 billion) was insured.

Climate patterns, including a “coastal El Nino phenomenon” affected atmospheric circulation over the US, helping generate super-cell storms that brought hailstones as big as 11cm.

“The exceptional accumulation of severe thunderstorms in the US highlights just how important it is for insurers to have in-depth knowledge of natural catastrophes and how these are affected by climatic changes,” Munich Re board member Torsten Jeworrek said.

Munich Re says floods in Peru in February and March were the most expensive event, with losses of $US3.1 billion ($4 billion), of which only $US380 million ($486 million) was insured. Australia’s Cyclone Debbie was the second-costliest, with overall losses of $US2.7 billion ($3.5 billion) and insured losses of $US1.4 billion ($1.8 billion).

“In terms of actual loss amounts, Asia and Australia were not as badly hit by natural disasters as they often are,” Munich Re board member responsible for the region Hermann Pohlchristoph said.