Natural catastrophes across the globe in September caused tens of billions of dollars in economic losses, according to insurance broker Aon PLC's latest Global Catastrophe Recap report.

Economic losses from Hurricane Florence, the costliest of two storms to make landfall in the U.S. during the month, will exceed US$10 billion, the broker said. It expects insured losses to be "in the low-digit billions" because of low flood insurance penetration.

Economic losses from Typhoon Jebi, which led to significant wind and flood damage in several prefectures in Japan, will "reach well into the billions of dollars," according to Aon. Insurance payouts reaching into the billions are expected from that storm too. Nearly 486,000 claims have been filed, Aon added, citing the General Insurance Association of Japan.

Super Typhoon Mangkhut, which hit the Philippines, Hong Kong and China, is expected to trigger combined economic damage and business interruption in the billions of dollars. Local insurers in China and Hong Kong are expecting to pay claims "approaching or exceeding" $1 billion, Aon said.

Also, total economic damage from the magnitude 7.5 earthquake and tsunami in Indonesia is expected to approach $1 billion.