Mountains cause enhanced rainfall in Puerto Rico

ROANOKE, Va. (WDBJ) - Hurricane Fiona had major impacts in the Caribbean with intense rainfall causing flooding issues in Puerto Rico. Puerto Rico is located along two tectonic plates, the Caribbean and the North American, which formed the various mountain ranges on the island.

Map of Puerto Rico from National Geographic Society. — Map of Puerto Rico from National Geographic Society.(National Geographic Society)

Hurricane Fiona’s eye passed South of the island and turned towards the North and passed over the Dominican Republic. The bands of Fiona on the east side of the storm were in the perfect setup for enhanced rainfall. The bands were coming from the South and lifting over the mountains bring more rainfall to parts of the island than others. This process is called orographic lift.

Bands from Hurricane Fiona cause flooding in Puerto Rico. — Bands from Hurricane Fiona cause flooding in Puerto Rico.(WDBJ)

Hurricane Fiona brought more rain to Puerto Rico than Hurricane Maria in 2017. — Hurricane Fiona brought more rain to Puerto Rico than Hurricane Maria in 2017.(WDBJ Weather)

This is also a possibility in Southwest Virginia. If a tropical system comes through and the bands come into the region at just the right direction (mainly from the Southeast) enhanced rainfall is likely. This is just one reason we watch tropical systems so closely.

The elevation of the mountains of Puerto Rico are very similar to the the Blue Ridge and Appalachian mountains. Below is an explainer of the highest peak in Puerto Rico and Mount Rodgers.

Orographic lift impacted Puerto Rico and can impact Southwest Virginia with the right setup.

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