With winds of 125mph (205km/h), the storm is expected to arrive in southern Florida by early Friday.
The hurricane has already caused havoc in Bahamas, and in Haiti, where 108 have died. The storm has also killed four people in Dominican Republic.
On Thursday, USA President Barack Obama declared a state of emergency for Florida, as two million people have already been evacuated.
"There are no excuses, you need to leave," Florida Governor Rick Scott warned people who are still in the evacuation zones. The Florida Governor also said, "Everyone in our state must prepare now for a direct hit...if Matthew directly impacts Florida, the destruction could be catastrophic and you need to be prepared."
to predict - to make a theory about the future
fierce - very powerful and destructive
havoc - great destruction and chaos (disorder)
catastrophic - totally destructive (causing a catastrophe)