Puerto Rico, 2021

Flash Flooding and Debris Flows in Puerto Rico, October 13 to 16, 2021

October 13 to 16, 2021 · NWS SJU · 12 events in 4 counties and zones

A surface low located north of the area resulted in southerly winds and dragged plenty of moisture into the area for several days. This feature also resulted in weak steering flow.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
$4,000
Crop damage
None recorded
Events
12

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS SJU wrote it up.

A surface low located north of the area resulted in southerly winds and dragged plenty of moisture into the area for several days. This feature also resulted in weak steering flow. This aided in the generation of slow-moving shower and thunderstorm activity each afternoon across various sectors of Puerto Rico.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Juan, PR wrote its last area forecast discussion before the first event at Oct 13, 10:55 AM AST, 3 hours 35 minutes earlier.

Area forecast discussion, Oct 13, 10:55 AM AST, 3 hours 35 minutes before
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Hazardous weather outlook, Oct 13, 3:54 AM AST, 10 hours 36 minutes before
Perspectivas sobre las Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorologia en San Juan PR
352 AM AST miercoles 13 de octubre de 2021

AMZ710>745-PRZ001>013-140800-
San Juan y Vecindad-Noreste-Sureste-
Este Interior-Norte Central-Interior Central-Ponce y Vecindad-
Noroeste-Oeste Interior-Mayaguez y Vecindad-Suroeste-Culebra-Vieques-
Las aguas costeras cercanas y lejanas a la costa del Atlantico y
Caribe-
352 AM AST miercoles 13 de octubre de 2021

Esta Perspectiva sobre las Condiciones Peligrosas del Tiempo es para
Puerto Rico y las aguas costeras adyacentes del Atlantico.

.Dia Uno...Hoy y esta noche

.Tronadas...Existe una probabilidad de tronadas con lluvia
fuerte y vientos en rafaga esta tarde a traves de la mayoria del
area.

.Inundaciones...Lluvia fuerte pudiera resultar en inundaciones
urbanas y de pequenos riachuelos.

.Oleaje...Se espera oleaje picado de hasta 7 pies a traves de
sectores de las aguas expuestas del Atlantico y hasta 6 pies en el
resto del area.

.Corrientes marinas...Existe un riesgo alto de corrientes
marinas para todas las playas del norte de Puerto Rico y para todo
Culebra. Existe riesgo moderado de corrientes marinas para las
playas de Rincon y Aguada, el sureste y para Vieques.

.Dias dos hasta el siete...jueves a martes

El riesgo de inundaciones urbanas y de riachuelos por aguaceros y
troandas continuara por el resto de la semana laboral. El riesgo
moderado de corrientes marinas continuara hasta el viernes.

.Comunicado sobre informacion reportada por observadores...

No se espera activacion amplia de observadores. Favor de reportar
cualquier informacion sobre inundaciones, vientos, oleaje y
corrientes marinas al Servicio Nacional de Meteorologia en San Juan
mientras siguen las indicaciones de las autoridades locales y
estatales.

AMZ710>745-PRZ001>013-140800-
San Tomas, San John e Islas Adyacentes-
Santa Cruz-Aguas cercanas del Atlantico y aguas costeras adyacentes
del Caribe-
352 AM AST miercoles 13 de octubre de 2021

Esta perspectiva sobre las condiciones peligrosas del tiempo es para
Islas Virgenes Estadounidenses y las aguas costeras adyacentes.

.Dia Uno...Hoy y esta noche

.Tronadas...Existe una probabilidad de tronadas con lluvia
fuerte con rafagas de viento esta tarde a traves de las islas.

.Inundaciones...Lluvia fuerte pudiera resultar en inundaciones
urbanas y de cunetas a traves de la region.

.Oleaje...Se espera oleaje picado de hasta 7 pies a traves de
sectores de las aguas expuestas del Atlantico y hasta 6 pies en el
resto del area.

.Corrientes marinas...Existe un riesgo moderado de corrientes
marinas para todas las playas.

.Dias dos hasta el siete...jueves a martes

El riesgo de aguaceros y tronadas continuara hasta al menos finales
de semana. El riesgo moderado de corrientes marinas hasta el jueves.

.Comunicado sobre informacion reportada por observadores...

No se espera activacion amplia de observadores. Favor de reportar
cualquier informacion sobre vientos, oleaje y corrientes marinas al
Servicio Nacional de Meteorologia en San Juan mientras siguen las
indicaciones de las autoridades locales y estatales.

The radar

The San Juan radar (TJUA), 31 km away, was scanning. The volume nearest the first event began at 18:31 UTC.

Open the radar archive at this moment

Event by event

5 flood, 5 flash flood, 2 debris flow. Local standard time, as filed.

Flood, San Juan

When
October 13, 2:30 PM AST to 5:00 PM AST
Where
San Juan County, 1.7 mi NW of San Juan to 1.78 mi NW of San Juan
Cause
Heavy Rain
Reported by
Emergency Manager
Coordinates
18.397, -66.069

Flooding reported in Urbanization Villa Nevarez, Calle 10, 3, 5.

Flood, San Juan

When
October 13, 2:30 PM AST to 5:00 PM AST
Where
San Juan County, 1.53 mi NW of San Juan to 1.4 mi NW of San Juan
Cause
Heavy Rain
Reported by
Emergency Manager
Coordinates
18.393, -66.069

One lane was intransitable along Road PR-21 in Rio Piedras due to flooding.

Flash Flood, San Juan

When
October 13, 3:00 PM AST to 5:00 PM AST
Where
San Juan County, 1.82 mi SSE of San Juan to 2.03 mi SSE of San Juan
Cause
Heavy Rain
Property damage
$500
Reported by
911 Call Center
Coordinates
18.355, -66.041

Residence flooded along Road PR-844 in Cupey.

Flood, San Sebastian

When
October 13, 5:15 PM AST to 6:45 PM AST
Where
San Sebastian County, 2.85 mi NW of San Sebastian to 2.88 mi NW of San Sebastian
Cause
Heavy Rain
Reported by
Emergency Manager
Coordinates
18.345, -67.005

Intersection of Road PR-125 and Road PR-446 impassable due to flooding from a small creek.

Flood, Bayamon

When
October 15, 3:00 PM AST
Where
Bayamon County, 2.98 mi NE of Bayamon to 2.96 mi NE of Bayamon
Cause
Heavy Rain
Reported by
911 Call Center
Coordinates
18.384, -66.142

Flooding reported along Avenida Main near Jardineria Esmeralda.

Debris Flow, Bayamon

When
October 16, 1:30 PM AST to 4:30 PM AST
Where
Bayamon County, 2.96 mi SSW of Bayamon to 2.99 mi SSW of Bayamon
Cause
Heavy Rain
Reported by
911 Call Center
Coordinates
18.309, -66.181

Mudslide reported along Road PR-8829 near Iglesia Pentecoastal Sector El Chicharo.

Flood, San Juan

When
October 16, 2:20 PM AST to 4:20 PM AST
Where
San Juan County, 1.52 mi WNW of San Juan to 1.48 mi NW of San Juan
Cause
Heavy Rain
Reported by
Emergency Manager
Coordinates
18.391, -66.070

Small stream in the Urbanization of Villa Nevarez went out of its banks, flooding Calle 5.

Flash Flood, San Juan

When
October 16, 2:20 PM AST to 4:20 PM AST
Where
San Juan County, 3.76 mi NW of San Juan to 3.67 mi NW of San Juan
Cause
Heavy Rain
Property damage
$1,000
Reported by
Emergency Manager
Coordinates
18.418, -66.091

Flooding reported along Avenida de Diego below the bridge of Expresso 22, trapping one person.

Flash Flood, San Juan

When
October 16, 2:20 PM AST to 4:20 PM AST
Where
San Juan County, 0.24 mi SW of San Juan to 0.28 mi WSW of San Juan
Cause
Heavy Rain
Reported by
Emergency Manager
Coordinates
18.378, -66.053

Flooding reported along Calle San Genaro in the Urbanization Sagrado Corazon.

Flash Flood, San Juan

When
October 16, 2:30 PM AST to 4:20 PM AST
Where
San Juan County, 2.73 mi WNW of San Juan to 2.7 mi NW of San Juan
Cause
Heavy Rain
Property damage
$1,000
Reported by
911 Call Center
Coordinates
18.401, -66.085

Two people trapped inside a vehicle in Calle 5SE intersection with Calle 16SE in the Urbanization of Cappara Terrace due to a small stream going out of its banks.

Flash Flood, San Juan

When
October 16, 2:55 PM AST to 4:20 PM AST
Where
San Juan County, 2.4 mi NW of San Juan to 2.16 mi NNW of San Juan
Cause
Heavy Rain
Property damage
$1,000
Reported by
911 Call Center
Coordinates
18.408, -66.071

A vehicle with people inside was trapped in Expresso Las Americas, Exit 5B, in the direction from Caguas to San Juan.

Debris Flow, Comerio

When
October 16, 4:55 PM AST
Where
Comerio County, 1.8 mi WSW of Comerio to 1.78 mi WSW of Comerio
Cause
Heavy Rain
Reported by
911 Call Center
Coordinates
18.209, -66.245

Mudslide reported along Road PR-156 near the intersection with Road PR-776.

What these are

Flood
Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Debris Flow
A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Puerto Rico in 2021Every state in 2021This day in weather historyWarnings in Puerto Rico, October 2021

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 986673, 986861, 987108, 987109, 987387, 987388, 987877, 987883, 987884, 987885, 987886, 987888.