Image of the Day: Torrential Rainfall in Puerto Rico

When Hurricane Maria swept across Puerto Rico on September 20, 2017, meteorologists expected it to deliver a tremendous amount of rain in a short period of time. Satellite data confirm that that is exactly what happened.

This map shows satellite-based measurements of rainfall in the Caribbean near Puerto Rico. It depicts measurements from the evening of September 18 to the evening of September 20. The brightest areas reflect the highest rainfall amounts—as much as 20 inches (500 millimeters) in places.

Rain bands trailing the storm continued to deliver heavy rain to the island on September 21-22. The National Hurricane Center reported catastrophic flooding, particularly in mountainous areas, and noted that mudslides should be expected. Mountainous terrain channels floodwater into streams and rivers. Gauges in these rivers show that many, such as the Rio Grande de Manati, have reached record-high levels.

After Maria left Puerto Rico, it moved on to the Dominican Republic and battered parts of the island with heavy winds and rain. According to news reports, most parts of this island saw at least 6–12 inches (150–300 millimeters), with some areas seeing as much as 20 inches (500 millimeters).