The cyclone is set to hit St Kitts and Nevis, Antigua and Barbuda by Friday evening, and Puerto Rico on Saturday.
Up to a full foot (30 centimetres) of rain could fall in parts of Puerto Rico as winds reach sustained speeds up to 65 miles per hour (105 kilometres per hour), bringing local flooding and dangerous conditions to the island – which faced serious devastation from Hurricane Maria almost exactly five years ago.
A tropical storm warning has been issued for St Kitts, Nevis, Antigua, Barbuda, Montserrat, Anguilla, St Maarten, Saba, St Eustatius, St Maarten, Guadaloupe, St Barthelemy, St Martin, Puerto Rico and the US Virgin Islands.
A tropical storm watch is also in effect for Dominica and the British Virgin Islands. The National Hurricane Centre (NHC) says further tropical storm watches are possible on Hispaniola, as the storm is forecast to reach the Dominican Republic on Sunday.
The intense rainfall could bring a serious risk of mudslides and local flooding, especially in urban areas, the agency adds. The National Weather Service (NWS) has warned that flooding impacts in Puerto Rico could be “extensive”.
“These rains may produce flash and urban flooding, along with isolated mudslides in areas of higher terrain,” NWS warns.
The island’s coastlines are also at high risk of dangerous rip currents.
Fiona is expected to slowly grow stronger over the next few days, and could be “near hurricane strength” as it reaches the Dominican Republic, NHC says.
After that, the storm is likely to grow stronger again as it hits the ocean again, and the agency says it will likely strengthen into a hurricane at some point as it nears Turks and Caicos and the Bahamas. AccuWeather reports that the after that, Fiona’s path is less clear – but that people on the eastern coast of the US should keep an eye on it.
— NWS San Juan (@NWSSanJuan) September 15, 2022
In addition to high winds, between three and six inches of rain are likely to fall in the storm’s path, including in Puerto Rico and possibly the Dominican Republic as the storm heads further east.
The storm is just the sixth named storm of the Atlantic hurricane season, which has been off to a slow year. So far, just two hurricanes have formed — neither of which was stronger than Category 2 — even as the hurricane season enters its usual peak in mid-September.
2022 was also the first year since 1997 that no named storms formed in the month of August.
The US National Oceanic and Atmospheric Administration (NOAA) had forecast an “above-normal” hurricane season this year, with up to 21 named storms, including up to 10 hurricanes. The Atlantic hurricane season lasts from June through November.
In 2017, Hurricane Maria had become a Category 4 hurricane by the time it hit Puerto Rico, leaving unimaginable damage in its wake. Most of the island went without power for weeks afterwards, and much of the islands was similarly without running water for weeks.
Nearly 3,000 people in Puerto Rico died as a result of the storm and its aftermath, making Maria one of the deadliest US hurricanes in recent memory.
Despite the relatively quiet year so far, hurricanes are expected to become much stronger on average as the climate crisis grows. Warmer air and water can create storms with much more rain and faster winds — making them vastly more dangerous as they make landfall.