The most forceful Atlantic storm ever has hit Caribbean. The category five hurricane, the highest possible level, has sustained wind speeds reaching 300km/h (185mph).It first hit Antigua and Barbuda, before moving on to Saint Barthelemy and Saint Martin.
The French weather officials say major flooding has been caused in their low-lying areas.
It is then expected to move on towards Puerto Rico and the Dominican Republic.
The latest forecast track map from the National Hurricane Center predicts that Irma will reach Puerto Rico at 8pm CDT today then moving northwest, passing the Dominican Republic at 8am on Thursday, and the Turks and Caicos Islands at 8pm. Tropical storm forces winds will reach the Bahamas overnight.
The storm will pass over or near Cuba at 8pm on Friday, and will reach the southernmost tip of Florida at 8pm on Sunday.