Tropical Storm Isaac churned across the Gulf of Mexico yesterday, disrupting US offshore energy production and threatening to hit Louisiana on the anniversary of the devastating Hurricane Katrina in 2005.

A weakening Tropical Storm Paula dumped heavy rain on Cuba’s capital, Havana, turning some of the streets into shallow rivers and knocking out power before sliding along the island’s northern coast.

Insurance market Lloyd’s of London today estimated that claims arising from hurricanes Gustav and Ike would cost it around £1.3bn (€1.67bn).

Global warming may have made Hurricane Gustav slightly stronger and wetter, some scientists said today, but few were rushing to make a specific connection between climate change and stronger storms.