The past three months may stand as one of the worst quarters on record for natural disasters, according to Aon Benfield subsidiary Impact Forecasting.

The scale of damage caused by hurricanes Irma and Maria is still being calculated, according to the modeller’s summary of last month’s catastrophes, but the dollar toll of each is “expected to reach well into the tens of billions”.

The US National Hurricane Centre says last month was the most active recorded for tropical cyclones in the Atlantic Ocean.

Elsewhere last month, Mexico was hit by Tropical Storm Lidia, which killed 20 people when it tracked along the Baja Peninsula, and three powerful earthquakes.

The quakes included the strongest of the year: a magnitude-8.1 event that struck offshore, killing at least 103 people. A magnitude-7.1 quake then struck central Mexico, killing 367 people and injuring thousands more.

Combined economic damage is expected to reach into the billions of dollars.

“September was exceptionally busy and marked by the most active month on record in the Atlantic Ocean for hurricanes based on combined strength and longevity,” Impact Forecasting Meteorologist Steve Bowen said.

“The most prolific damage resulted from Hurricane Irma’s impact across the US and the Caribbean, and Hurricane Maria’s track through the Caribbean.

“These events [are] poised to cause a heavy financial burden for federal governments and the insurance industry.

“Additionally, two major earthquakes and a powerful aftershock in Mexico led to catastrophic damage. When combining event impacts from July and August, the third quarter… is expected to tally as one of the costliest quarters ever registered for natural disasters.”