Simplify the following text for a Grade 10 native English-speaking person.
Original: A few hours later , the storm entered the Gulf of Mexico and intensified rapidly into a Category 5 hurricane while crossing the Loop Current on August 28 . Katrina made landfall on August 29 near the mouth of the Mississippi River as an extremely large Category 3 hurricane .
Simplified: Hurricane Katrina was a powerful category 5 hurricane .