From 21 September to 6 October 2017, a Zone of Intertropical Convergence (ZCI), characterized by the entry of humidity from the Pacific Ocean and the Caribbean Sea, Tropical Wave No. 42 and the formation of formation of Tropical Wave No.16, which developed into Tropical Storm Nate on 5 October 2017, caused flooding throughout Cosa Rica.
The CNE declared a red alert, following the National Weather Institutes issuance of a warning on 4 October 2017.
From 4 to 5 October, the cumulative rainfall exceeded 400 mm in Guanacaste, while the cumulative rainfall ranged from 150 to 250 mm in some sectors of the Central Valley, leading to oversaturation of the soil in the affected areas.
Roads have been affected, impeding access to the communities. The National Societys response teams were mobilized by air to the affected areas to stage rescues and evacuations. The following data has been reported onset of the inclement weathers impact on Costa Rica:
A red alert is being maintained in the Central Pacific, South Pacific, North Pacific, North Huetar and Central Valley regions, while a yellow alert is being maintained in the Huetar Caribe region. The latest situation report from the Costa Rican governments CNE reported the following damage.