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.

Rescue workers were today considering evacuating New Orleans as it faced a hurricane threat three years to the day that Katrina devastated the city.

Rain from Tropical Storm Ernesto swept across parts of the vulnerable Florida Keys today as residents hurried to fill petrol tanks, gather emergency supplies and board up windows before the main body of the storm strikes.

Hurricane Iris strengthened into the Atlantic’s most powerful hurricane of the year as it advanced across the Caribbean toward Central America tonight bringing winds of up to 140 mph.