Isaac moves north after drenching U.S. Gulf, New Orleans

Tropical storm Isaac is expected to weaken further as it heads north on Thursday, after causing significant damage to the U.S. Gulf Coast but nothing on the scale of Hurricane Katrina, which devastated New Orleans in 2005. The former Category One hurricane was likely to become a tropical depression on Thursday, and could still bring heavy rain and floods as it moved across the center of the country over the next few days, the National Hurricane Center said. As Isaac ebbs, probes should show an elaborate flood containment plan developed for low-lying New Orleans survived its first major test, seven years to the day after Katrina laid waste to the city and killed more than 1,800 people.