Explainer: Ida and Katrina similar but tiny differences are key

Category 4 Hurricane Ida is on track for a potentially devastating landfall on the Louisiana coast on Sunday.

Hurricane Ida is looking eerily like a dangerous sequel to 2005’s Hurricane Katrina, the costliest storm in American history. But there are a few still-to-come twists that could make Ida nastier in some ways, but not quite as horrific in others. Ida is forecast to make landfall on the same calendar date, August 29, as Katrina did 16 years ago, striking the same general part of Louisiana with about the same wind speed, after rapidly strengthening by going over a similar patch of deep warm water that supercharges hurricanes. What could be different is crucial though: direction and size.