Tropical Storm Nate has killed at least 22 people in Costa Rica, Nicaragua and Honduras before it moves north towards the US, BBC reports.
A state of emergency has been declared in the Central American nations, where more than 20 people are missing.
It has caused heavy rains, landslides and floods which are blocking roads, destroying bridges and damaging houses.
In Costa Rica, nearly 400,000 people are without running water and thousands are sleeping in shelters.
At least eight people have died in the storm there, while another 11 were killed when it moved north and reached Nicaragua, where as much as 15ins (38cm) of rain had been predicted to fall by the US's National Hurricane Center.
Three people have been killed in Honduras, including two youths who drowned in a river, and several are reported missing.