Flood — Patillas, Puerto Rico

2011-09-12 to 2011-09-13 · near Patillas, Patillas, Puerto Rico

Event narrative

Flood waters covered many sections of Patillas municipality. Two low crossing bridges at Barrio Marin, Los Barros sector collapsed, and several homes were isolated. Another bridge collapsed at Barrio Cacaboa, Los Pompos sector isolating eight homes, and at Barrio Icacos La Mula sector. Rivers Marin, Providencia and Los Pollos were reported out of their banks, flooding seven homes in the Providencia neighborhood.

Wider weather episode

Maria was first designated Tropical Depression 14 on September 6 in the far eastern Atlantic. By the following day the depression was upgraded and named Tropical Storm Maria at 1100 am AST, the 13th named storm of the season, while it was moving rapidly westward. At 11 pm AST on Thursday September 8 a tropical storm watch was issued for the U.S. Virgin Islands and Puerto Rico. At 5 am AST September 9 a tropical storm warning was issued for the U.S. Virgin Islands, and at 11 am the warning was extended for Puerto Rico. Maximum winds in Maria remained between 40 mph and 50 mph for several days. On Sunday, September 11, an air force reconnaissance aircraft reported that it was becoming better organized, just 65 mi northeast of Saint John Island. The U.S. Virgin Islands experienced breezy to windy conditions for 3 days while Maria was not far away, but not to a level of causing significant damage. The maximum winds recorded at locations where at least 25 mph. Rather than the large scale strong winds usually found in tropical storms the most intense wind on these islands often occurred during rain squalls, when showers force winds aloft to sink towards the surface. This caused the strongest sustained wind recorded during this event. The Saint Thomas airport recorded a maximum sustained southerly wind of 33 mph with gusts to 48 mph at 1 pm AST on September 12th, the rest of the recorded winds across the U.S. Virgin Islands were of lesser strength. On September 12 bands of heavy showers were developing in the moist 'tail' of Maria, focusing mainly on the U.S. Virgin Islands. The slow movement of Maria, the moist tail being dragged along towards the south, and the mountain terrain of across Puerto Rico would prove to be a fateful combination, especially on the night of the 12th and morning of the 13th. Puerto Rico had devastating flooding rain for the third time in 6 weeks, following Tropical Storm Emily and Tropical Storm/Hurricane Irene, and after the extraordinarily rainy summer of 2011. Early on September 13 Maria was located north of the west end of Puerto Rico. There were developing rain bands that extended west to east, up the central mountain range in Puerto Rico, and also on the south side of the Luquillo Mountains at the eastern portion of the island. Most soils across Puerto Rico were already saturated from an extraordinarily wet summer including rain from two other tropical storms in the previous 6 weeks. Rain became the major problem as Maria became almost stationary on September 13. Rainfall accumulations were between 4 to 6 inches with locally higher amounts of up to 10 inches. The hardest hit communities were on the southern slopes of Puerto Rico including the communities along the larger rivers with headwaters in the south and south central sections of the island. Larger river basins such as the Rio de la Plata, Rio Grande de Loiza, Rio Grande de Arecibo and Rio Grande de Manati and their tributaries showed significant rises with minor to moderate flooding reported. The smaller basins along the southern slopes experienced flash flooding with the high intensity rainfall. Residents in the communities of Juana Diaz, Salinas and Ponce experienced some of the highest flows of the past few years especially on Rivers Toa Vaca and Jacaguas. The tropical storm warning for the U.S. Virgin Islands and Puerto Rico was discontinued at 11 am AST on September 10. Around 15,600 residents were without commercial power.

View location on OpenStreetMap → (18.0214, -66.0302)

Source: NOAA Storm Events Database, event_id 349577. Narrative written by the NWS forecast office that issued the report.