PORT-AU-PRINCE: Haiti was hammered by heavy rain on Sunday from Tropical Storm Laura, as a second tropical storm, named Marco, was forecast to strengthen into a hurricane and hit the US state of Louisiana on Monday.

The US National Hurricane Center said Storm Laura was "bringing torrential rainfall and life-threatening flooding" to Haiti, which shares Hispaniola island with the Dominican Republic.

A 10-year-old girl died on Sunday morning in Haiti when a tree fell on a house, according to authorities, who added some homes were flooded and evacuations were underway. The storm earlier passed over Puerto Rico.

The Atlantic storm season, which runs through November, could be one of the busiest ever this year, with the Hurricane Center predicting as many as 25 named storms. Laura is the 12th so far.

Haiti, a country of 11 million, has seen a relatively low incidence of COVID-19 - with just over 8,000 cases and around 200 deaths to date - but authorities urged caution to prevent further spread in the aftermath of Storm Laura.

Storms pose a serious risk to Haiti every year from June to November. Even a heavy rainfall can threaten the country's poorest residents, many of them living in at-risk zones, near canals or ravines that can be obstructed by debris and quickly overflow. After reaching hurricane-strength, Storm Marco is predicted to weaken rapidly after moving inland across Louisiana on Monday and Tuesday.