Flash Flood — St. Thomas, Virgin Islands

2024-08-14 · near St Thomas, St. Thomas, Virgin Islands

Event narrative

The public reported flash flooding occurring in Garden Street near Emancipation Gardens Park. The road was impassable and fallen trees were floating around.

Wider weather episode

The US Virgin Islands were under a Tropical Storm Warning due to the tropical cyclone threats associated with Ernesto. Ernesto approached the islands late Tuesday night into Wednesday as a tropical storm intensified into a hurricane across the Atlantic Ocean northwest of St Thomas on the 14th at around 11 AM AST. Before the event unfolded, the CoCoRaHS network also showed that the Virgin Islands received above-normal rainfall, ranging from 4 to 7 inches in the 30 days preceding the storm across all the islands.

The first rainbands associated with the tropical storm arrived on Tuesday under a northeasterly wind flow. During the night hours of Tuesday, the first strong area of rainfall reached the Virgin Islands. The system quickly dumped over four inches of rainfall across the islands, triggering flash flooding.

Strong gusty winds were observed as the hurricane's outer rainbands moved over the islands. The highest wind gust recorded in the Virgin Islands was 79 mph on Buck Island, Saint Thomas. Reports included fallen trees, downed power lines, and other damages.

Ernesto brought significant flooding, along with tropical storm-force sustained winds and hurricane-force wind gusts, which caused substantial damage across the US Virgin Islands. Nearly 65% were associated with wind gust damage and tropical cyclone conditions, while 32% were associated with flooding and landslides. The power grid was affected by the tropical-force winds and heavy rains. The initial estimates for the damages caused by Ernesto are approximately 5 million dollars.

View location on OpenStreetMap → (18.3419, -64.9329)

Source: NOAA Storm Events Database, event_id 1214544. Narrative written by the NWS forecast office that issued the report.