Category 5 Hurricane Irma makes landfall in Antigua and Barbuda

Hurricane Irma, which has been described as "potentially catastrophic" and is now the most powerful Atlantic storm in history, has made landfall in parts of the Caribbean.

The storm, which is a category 5, has already sustained winds of more than 185mph and has sparked mass evacuations.

Storms that are ranked as category 5 are the rarest but also the deadliest, bringing strong winds, storm surges and extreme flooding. Hurricane Harvey, which killed dozens and caused widespread flooding in Texas two weeks ago, was a category 4.

Irma has already hit Antigua and Barbuda and is expected to slowly make its way northwest towards the United States.

But for those areas that are in the way of Irma, the potential for lasting damage has increased due to the slow nature of the hurricane which is moving at just 15mph.

Estimated Hurricane Irma timeline (All times AST (Atlantic Standard Time):

• Wednesday- 2am- Antigua and Barbuda
• Thursday- 2am- Puerto Rico
• Friday- 1am- Haiti and the Dominican Republic
• Saturday- 12am- Cuba
• Sunday- 2am- Florida, USA

Hurricanes and storms tend to ease as they head over cooler areas and land, but the warmer than usual warmer waters have fuelled Irma, helping the storm to maintain strong winds.

Donald Trump has declared a state of emergency in Florida, Puerto and the US Virgin Islands with mandatory evacuations currently underway in parts of Miami-Dade.

The storm overnight began to hit eastern Caribbean islands including Dominica and Guadeloupe, and is currently progressing over Antigua and Barbuda.

In Antigua and Barbuda, islanders have boarded up homes and taken shelter as the storm strikes.

An anemometer that was measuring winds in Barbuda reached 155mph before it was ripped away from a weather centre.

Some on the island have reported that the storm has quietened down, though this is most likely due to the eye of the storm passing over the area.

But with power down in much of the island, communication has been limited.

At over 400 miles wide, Irma dwarfs Barbuda which is around 10 miles wide.

Many buildings on the islands are not built on concrete foundations and most have wooden roofs that are highly susceptible to wind damage.

St Kitts and Nevis is next to be hit by the storm with many already indoors and in shelters.

Prime Minister Timothy Harris urged the public to remain indoors as the "extremely dangerous" storm passes over the island.

Meanwhile in the Bahamas, which is due to be in in the next 24-48 hours, officials have ordered the largest hurricane evacuation in the history of the island.

Prime Minister Hubert Minnis warned that emergency services may not be able to reach those who are caught up in the heart of the storm when it strikes.