Flash Flooding and Debris Flows in Puerto Rico, April 13, 2010

Name: Flash Flooding and Debris Flows in Puerto Rico, April 13, 2010
Start: 2010-04-13T10:13
End: 2010-04-13T23:00
Location: Puerto Rico

April 13, 2010 · NWS SJU · 7 events in 7 counties and zones

Subtropical jet located north of Puerto Rico combined with a mid to upper level disturbance which resulted in the development of scattered to numerous showers and a few thunderstorms across parts of Puerto Rico.

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: $45,000
Crop damage: None recorded
Events: 7

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.

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 Apr 13, 9:28 AM AST, 45 minutes earlier.

Area forecast discussion, Apr 13, 9:28 AM AST, 45 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
928 AM AST TUE APR 13 2010

.UPDATE...HEAVY SHOWERS NOW IN PROGRESS OVER EXTREME EASTERN
PUERTO RICO AND MODERATE SHOWERS COMING FOR SAINT THOMAS. SHOWERS
ON SOUTHEAST COAST SHOULD BE BRIEF HOWEVER. ISSUED URBAN AND SMALL
STREAM FLOOD ADVISORY FOR AMOUNTS OF UP TO 3 INCHES AND 6 HOUR
GAGE TOTAL ON WESTERN FRINGE OF PRECIPITATION AREA IS ABOVE 2
INCHES. THIS RAIN SHOULD ABATE BY NOON BUT HAVE UPDATED GRIDS TO
REFLECT CURRENT SITUATION. QPS PRODUCT DOES NOT REFLECT BEST RAIN
AREAS SINCE BASINS ARE MORE INLAND...BUT HAVE UPDATED TOTALS THERE
TOO. WESTERN PUERTO RICO'S RAIN SHOULD BEGIN AFTER NOON.

&&

.DISCUSSION...SOUNDING SHOWS VERY MOIST LOWER LEVELS AND UNSTABLE
CONDITIONS TO 45 THOUSAND FEET. SINCE GOOD MOISTURE NOW GOES TO 24
THOUSAND FEET EXPECT GOOD SHOWER ACTIVITY AND ISOLATED
THUNDERSTORMS OVER WESTERN PUERTO RICO AFTER NOON AND SOME SHOWERS
COULD OCCUR ANYWHERE IN THE AREA.

&&

.AVIATION...MORE EXTENSIVE MVFR AND MOUNTAIN OBSCURATION SHOULD BE
EXPERIENCED IN EASTERN PUERTO RICO THROUGH 13/17Z...AND AFTER
13/17Z ISLAND WIDE.

&&

.PREV DISCUSSION... /ISSUED 522 AM AST TUE APR 13 2010/

SYNOPSIS...AT MID AND UPPER LEVELS...WINDS OVER THE AREA ARE WEST
DUE TO HIGH PRESSURE SOUTHEAST OF THE WINDWARD ISLANDS AND A
PASSING TROUGH TO THE NORTH. THERE IS A STRONG JET BETWEEN 20 NORTH
AT UPPER LEVELS THAT WILL HAVE A DIRECT INFLUENCE ON THE WEATHER
THROUGH FRIDAY.

DISCUSSION...SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUED TO AFFECT THE LOCAL ATLANTIC OFF SHORE
WATERS. ALSO SCATTERED SHOWERS AFFECTED THE EASTERN PORTION OF
PUERTO RICO...CULEBRA...VIEQUES AND THE USVI. THESE SHOWERS HAVE
REMAINED CONSISTENT THROUGH THE OVERNIGHT HOURS...THEREFORE EXPECT
MORE SHOWERS TO MOVE ONSHORE AND AFFECT THE EASTERN AND SOUTHERN
PORTIONS OF PUERTO RICO.

SIGNIFICANT CHANGES IN THE WEATHER PATTERN HAVE ALREADY STARTED AS
THE SUB TROPICAL JET IS NOW SITUATED NORTH OF OUR LOCAL FORECAST
AREA. THIS FEATURE WILL BRING MID LEVEL SHORT WAVES ACROSS THE
AREA THROUGH THE INCOMING WEEKEND. THESE SHORT WAVES WILL HELP IN
THE ENHANCEMENT OF AFTERNOON CONVECTION AND OVERNIGHT SHOWERS.
THE LOCATION OF THESE SHOWERS AND THUNDERSTORMS WILL BE TRICKY AS
MODELS SUGGEST THE DEVELOPMENT OF A LOW LEVEL LOW PRESSURE
SOMEWHERE IN OUR LOCAL REGION. WIND PATTERNS GENERATED BY THIS
LOW WILL DICTATE WHERE SHOWERS WILL BE CONCENTRATED. WE BASED
THIS FORECAST ON THE LATEST RUN OF THE GFS MODEL...WHERE THE LOW
LEVEL LOW PRESSURE DEVELOPS NORTHEAST OF PUERTO RICO.

AVIATION...GENERALLY VFR CONDITIONS SHOULD PREVAIL ACROSS ALL TAF
SITES DURING THE MORNING HOURS. HOWEVER...BRIEF PERIODS OF MVFR
CONDITIONS ARE POSSIBLE ACROSS TJSJ...TISX...TIST...AND TJPS IN
PASSING SHOWERS. DURING THE AFTERNOON HOURS...MVFR CONDITIONS AND
LOCAL MOUNTAIN OBSCURATIONS ARE POSSIBLE ACROSS TJMZ...AND TJBQ
THROUGH 13/23Z.

MARINE...WINDS WILL CONTINUE TO SLIGHTLY DECREASE TODAY AND
THEREFORE SEAS WILL SUBSIDE TO BELOW SCA CRITERIA ACROSS ALL LOCAL
WATERS. MARINER SHOULD MONITOR OUR FORECAST AS DANGEROUS MARINE
CONDITIONS COULD DEVELOP AFTER THURSDAY AS A HIGH PRESSURE BUILDS
ACROSS THE REGION INCREASING THE WINDS AND SEAS ACROSS ALL THE LOCAL
WATERS. THESE FRESH TO STRONG WINDS ARE EXPECTED TO GENERATE
CONFUSED SEAS THROUGH THE WEEKEND. THIS MARINE FORECAST IS BASED ON
THE DEVELOPMENT OF THE LOW LEVEL PRESSURE DEVELOPING NE OF THE LOCAL
REGION.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  77  88  76 /  50  30  40  40
STT  85  76  86  77 /  50  50  50  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&

23/12

Hazardous weather outlook, Apr 13, 5:46 AM AST, 4 hours 27 minutes before

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
546 AM AST TUE APR 13 2010

AMZ710>745-PRZ001>013-141000-
SAN JUAN AND VICINITY-NORTHEAST-SOUTHEAST-EASTERN INTERIOR-
NORTH CENTRAL-CENTRAL INTERIOR-PONCE AND VICINITY-NORTHWEST-
WESTERN INTERIOR-MAYAGUEZ AND VICINITY-SOUTHWEST-CULEBRA-VIEQUES-
THE NEARSHORE AND OFF SHORE ATLANTIC AND CARIBBEAN COASTAL WATERS-
546 AM AST TUE APR 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE
ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

SCATTERED TO NUMEROUS SHOWERS WITH ISOLATED THUNDERSTORMS ARE
POSSIBLE TODAY...WHICH COULD PRODUCE PERIODS OF HEAVY RAINFALL.
URBAN AND SMALL STREAM FLOODING ARE LIKELY...MAINLY OVER THE
WESTERN INTERIOR AND WEST SECTIONS OF PUERTO RICO.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SIGNIFICANT INCREASE IN MOISTURE...COMBINE WITH FAVORABLE UPPER
LEVEL ATMOSPHERIC CONDITIONS ARE EXPECTED TO BEGIN DURING MID
WEEK...WHICH COULD LEAD TO EPISODES OF HEAVY RAINFALL AT ANY TIME
FROM WEDNESDAY THROUGH AT LEAST FRIDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME. HOWEVER...COULD
BE REQUIRED AT ANY TIME DURING THIS WEEK.

AMZ715-725-VIZ001-002-141000-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
546 AM AST TUE APR 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND
THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SIGNIFICANT INCREASE IN MOISTURE...COMBINE WITH FAVORABLE
UPPER LEVEL ATMOSPHERIC CONDITIONS ARE EXPECTED TO BEGIN DURING
MID WEEK...WHICH COULD LEAD TO EPISODES OF HEAVY RAINFALL AT ANY
TIME FROM WEDNESDAY THROUGH AT LEAST FRIDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME.
HOWEVER...COULD BE REQUIRED AT ANY TIME THIS WEEK.

The radar

The San Juan radar (TJUA), 38 km away, was scanning. The volume nearest the first event began at 23:53 UTC.

Open the radar archive at this moment

Event by event

4 flash flood, 3 debris flow. Local standard time, as filed.

Debris Flow, Ponce and Vicinity

When: April 13, 10:13 AM AST
Where: Ponce and Vicinity forecast zone
Reported by: Emergency Manager

Landslide along Highway 52, Km 63.8 in Santa Isabel.

Debris Flow, San Juan and Vicinity

When: April 13, 3:39 PM AST
Where: San Juan and Vicinity forecast zone
Reported by: Emergency Manager

Landslide along road 167, Camino de Los Nieves in Barrio Buena Vista, Bayamon.

Debris Flow, Mayaguez and Vicinity

When: April 13, 5:49 PM AST
Where: Mayaguez and Vicinity forecast zone
Reported by: Emergency Manager

Landslide along road 106, Km. 8.5, Barrio Mateyes in Mayaguez.

Flash Flood, San Juan

When: April 13, 7:52 PM AST to 11:00 PM AST
Where: San Juan County, 5.47 mi NNW of San Juan to 2.46 mi N of San Juan
Cause: Heavy Rain
Property damage: $45,000
Reported by: Emergency Manager
Coordinates: 18.456, -66.073

Locally heavy rains affected the northern sections of the San Juan Metropolitan area. Several homes and roads in poorly drained areas of Santurce and Hato Rey were reported flooded along with stranded vehicles.

Flash Flood, Luquillo

When: April 13, 8:01 PM AST to 9:00 PM AST
Where: Luquillo County, 1.26 mi E of Luquillo to 1.57 mi WNW of Luquillo
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 18.352, -65.701

Roads 983 and 940 were impassable due to flooding. Hacienda Carabali and the surrounding areas near Barrio Mameyes were reported flooded due to river Sabana overflowing its banks.

Flash Flood, Fajardo

When: April 13, 8:41 PM AST to 10:45 PM AST
Where: Fajardo County, 0.41 mi SW of Fajardo to 0.27 mi SSW of Fajardo
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 18.315, -65.654

Heavy rain along river Rio Fajardo caused it to overflow its banks along Highway 3 in the Paraiso area between Fajardo and Ceiba.

Flash Flood, Rio Grande

When: April 13, 8:45 PM AST to 10:45 PM AST
Where: Rio Grande County, 2.43 mi NE of Rio Grande to 2.24 mi NE of Rio Grande
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 18.370, -65.769

Road 191 that goes up into the Caribbean national Forest was flooded.

What these are

Debris Flow: A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.
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.

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

The same day elsewhere

Every storm in Puerto Rico in 2010 Every state in 2010 This day in weather history Warnings in Puerto Rico, April 2010

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: 226422, 226420, 226424, 226419, 226061, 226153, 226169.