Sargassum outlook

Where seaweed may reach the coast.

Sample content — not an operational product

The sargassum outlook is not yet published from the GMS forecast system. The figures on this page are illustrative and must not be used for any weather, marine or safety decision.

Outlook

Moderate amounts of sargassum are expected along the Atlantic-facing east and north-east coasts over the next two weeks. The south-west coast is expected to stay mostly clear.

What sargassum is

Sargassum is a floating brown seaweed. Since 2011, very large amounts have grown across the tropical Atlantic, and currents and trade winds carry mats of it into the eastern Caribbean, mostly from spring to autumn.

Grenada's Atlantic coast, including Bathway and Levera, sees the most. Satellites track the mats at sea, which lets us give a few weeks' notice of heavier arrivals.

If it washes up near you

Rotting sargassum releases hydrogen sulphide, with a smell like rotten eggs. People with asthma or breathing problems should avoid heavy build-ups.
Swim away from thick mats; they can hide jellyfish and tangle boat propellers.
Fishers: thick mats can block engine cooling intakes and harbour mouths.