Flash Flooding and Debris Flows in Puerto Rico, May 1 to 3, 2008

Name: Flash Flooding and Debris Flows in Puerto Rico, May 1 to 3, 2008
Start: 2008-05-01T11:40
End: 2008-05-03T10:00
Location: Puerto Rico

May 1 to 3, 2008 · NWS SJU · 15 events in 5 counties and zones

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: $50,000
Crop damage: None recorded
Events: 15

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 nearly stationary front, tropical moisture and interacting jet energy produced pockets of locally heavy rains which led to significant within bank rises on may rivers with some minor flooding reported along the local rivers. A couple of rivers responded quickly and went out of their banks. Since this was at the beginning of the month, river levels were running relatively high and the soils in the upper levels were moist in many areas. The Rio Grande de Arecibo, Rio Limon, Rio Cibuco, Rio Guajataca and Rio Culebrinas all exceeded flood stage in response to this rainfall event. Maximum rainfall amounts in the area stretching from the West Central to North and Western Puerto Rico, for the 24 hour period ending at 7 am on May 3rd, 2008 ranged from 3.5 to 4.5 inches. Flash Flooding and mudslides were reported in numerous areas around the island including Lares and Utuado. Two flash flood fatalities were reported in the Western Interior due to low water crossing in automobiles.

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 May 1, 5:38 AM AST, 6 hours 2 minutes earlier.

Area forecast discussion, May 1, 5:38 AM AST, 6 hours 2 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
538 AM AST THU MAY 1 2008

.DISCUSSION...THE NWS DOPPLER RADAR DETECTED SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS THE LOCAL REGIONAL WATERS AND ACROSS
THE EASTERN SECTIONS OF PUERTO RICO OVERNIGHT AND EARLY IN THE
MORNING. THE ESTIMATED TOTAL RAINFALL ACCUMULATIONS ASSOCIATED
WITH THIS ACTIVITY RANGED FROM 1 TO 2 INCHES MAINLY ACROSS
LUQUILLO...RIO GRANDE AND HUMACAO. NO SIGNIFICANT PRECIPITATION WAS
DETECTED ACROSS THE WESTERN HALF OF PUERTO RICO OVERNIGHT. A
FRONTAL TROUGH EXTENDING FROM THE CENTRAL CARIBBEAN...EAST
NORTHEAST ACROSS EASTERN CUBA AND CONTINUING EAST NORTHEAST ACROSS
THE SOUTHERN BAHAMAS AND INTO THE ATLANTIC...IS EXPECTED TO MOVE
SLOWLY TOWARD THE EAST SOUTHEAST DURING THE NEXT FEW DAYS. AT THE
SAME TIME A WEAKENING MID TO UPPER LEVEL RIDGE WILL REMAIN ACROSS
THE REGION ACTING TO INHIBIT THE DEVELOPMENT OF WIDESPREAD
THUNDERSTORMS ACROSS THE FA AT LEAST THIS AFTERNOON. HOWEVER...THE
AVAILABLE LOW LEVEL MOISTURE WILL COMBINE WITH THE EXPECTED STRONG
DAYTIME HEATING...SEA BREEZE CONVERGENCE AND LOCAL TERRAIN EFFECTS
TO PRODUCE CLOUDINESS...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS...MAINLY OVER PARTS OF THE INTERIOR AND WESTERN
SECTIONS OF PUERTO RICO THIS AFTERNOON AND FRIDAY AFTERNOON. SOME
OF THE RAINFALL WILL BE LOCALLY HEAVY AT TIMES AND MAY LEAD TO
URBAN AND SMALL STREAM FLOODING.

FOR THE UPCOMING WEEKEND...AS STATED IN THE PREVIOUS AFD...GFS
MODEL GUIDANCE SUGGESTS THAT A WEAK SURFACE LOW WILL DEVELOP
ACROSS EASTERN HISPANIOLA. THIS FEATURE WILL MOVE OVER OR NEAR THE
FA DURING THE WEEKEND CREATING AN AREA OF LOW LEVEL CONVERGENCE
AND WITH BETTER UPPER DYNAMIC...PROMOTING THE DEVELOPMENT OF
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS
ACROSS THE REGION. STAY TUNED FOR POSSIBLE WATCHES OR WARNING.

&&

.AVIATION...DURING THE MORNING HOURS...BANDS OF TRADE WIND MOISTURE
WILL CONTINUE TO MOVE ACROSS THE LOCAL FLYING AREA TO BRING PERIODS
OF SHOWERS TO THE VIRGIN ISLANDS AND EAST SECTIONS OF PUERTO RICO TO
INCLUDE TJSJ. TAF SITES IN THE NORTHERN LEEWARDS...TKPK AND TNCM
WILL ALSO BE AFFECTED AT LEAST UNTIL 14Z THIS MORNING. THE PASSING
CLOUDS AND SHOWERS WILL CAUSE BRIEF MVFR CONDITIONS...WHILE VFR
CONDITIONS ARE EXPECTED TO PREVAIL ELSEWHERE. DURING THE REST OF THE
DAY...LOW LEVEL MOISTURE AVAILABILITY COMBINED WITH DAYTIME HEATING
AND LOCAL EFFECTS WILL AGAIN LEAD TO AFTERNOON CONVECTION OVER THE
INTERIOR SECTIONS OF PR...WITH POSSIBLY BRIEF IFR CONDITIONS ACROSS
TJPS...TJSJ AND TJBQ IN A PASSING TSRA. INCREASING CLOUDINESS ACROSS
THE CORDILLERA CENTRAL  MAY ALSO CAUSE INTERMITTENT PERIODS OF
MOUNTAIN TOP OBSCURATIONS ESPECIALLY IN THE WEST INTERIOR BTWN
16-22Z.

&&

.MARINE...LONG PERIOD...NORTH NORTHEAST SWELLS WILL CONTINUE TO
SUBSIDE ACROSS THE LOCAL ATLANTIC WATERS AND THE CARIBBEAN PASSAGES
THIS MORNING. GENERALLY EXPECT WINDS OF 13 KNOTS OR LESS AND SEAS
OF 6 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH FRIDAY...
SMALL CRAFT OPERATORS SHOULD EXERCISE CAUTION ACROSS THE ATLANTIC
OFFSHORE WATERS TODAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  85  73  85  73 /  50  20  20  20
STT  81  73  81  73 /  40  20  20  20

&&

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

09/72/

Hazardous weather outlook, May 1, 6:24 AM AST, 5 hours 16 minutes before

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
624 AM AST THU MAY 1 2008

AMZ710>750-PRZ001>013-021030-
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-
624 AM AST THU MAY 1 2008

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

.DAY ONE...TODAY AND TONIGHT
SUFFICIENT LOW LEVEL MOISTURE TO COMBINE WITH LOCAL AND DIURNAL
EFFECTS TO PRODUCE AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS
MAINLY ACROSS THE INTERIOR AND WEST SECTIONS OF PUERTO RICO. SOME
OF THE RAINFALL WILL BE LOCALLY HEAVY AT TIMES...AND MAY TO LEAD
URBAN AND SMALL STREAM FLOODING. ALSO...RECENT RAINS HAVE LEFT WET
AND LOOSE SOILS ACROSS MUCH OF THE ISLAND. THEREFORE...THE POTENTIAL
FOR ROCK/MUDSLIDES REMAIN POSSIBLE IN AREAS OF STEEP TERRAIN.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

EXPECT THE PREVAILING EASTERLY TRADE WINDS TO CONTINUE TO BRING
PATCHES OF LOW LEVEL MOISTURE ACROSS THE REGION THROUGH THE END
OF THE WEEK AND INTO THE WEEKEND. LOCAL EFFECTS AND DAYTIME
HEATING WILL BE MORE THAN SUFFICIENT TO AID IN PRODUCING AFTERNOON
AND EVENING SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS ACROSS THE
INTERIOR AND WEST SECTIONS OF THE ISLAND. THE SHOWER ACTIVITY
MAY LEAD TO MINOR FLOODING OF URBAN AND POOR DRAINAGE AREAS...
AS WELL AS SMALL STREAMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

AMZ720-730-VIZ001-002-021030-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
624 AM AST THU MAY 1 2008

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.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

7 debris flow, 4 heavy rain, 2 flood, 2 flash flood. Local standard time, as filed.

Debris Flow, Central Interior

When: May 1, 11:40 AM AST
Where: Central Interior forecast zone
Reported by: Emergency Manager

Landslide was reported along road 159, Km. 6.5 from Corozal to Morovis. Two families were evacuated.

Flood, Central Interior

When: May 2, 1:00 PM AST to 3:00 PM AST
Where: Central Interior County, 3.67 mi W of Morovis to 3.08 mi W of Morovis
Cause: Heavy Rain
Property damage: $5,000
Reported by: Emergency Manager
Coordinates: 18.327, -66.475

A home was reported partially flooded near road 149, at Barrio Jaguas, Santa Clara sector, in the municipalaity of Ciales.

Heavy Rain, San Juan and Vicinity

When: May 2, 2:05 PM AST to 4:00 PM AST
Where: San Juan and Vicinity County, 1.86 mi WNW of San Juan
Reported by: Trained Spotter
Coordinates: 18.395, -66.074

A Skywarn spotter reported street flooding near the Medical Center in Rio Piedras and along the Americo Miranda Avenue.

Heavy Rain, Mayaguez and Vicinity

When: May 2, 2:35 PM AST to 5:00 PM AST
Where: Mayaguez and Vicinity County, Mayaguez
Reported by: Emergency Manager
Coordinates: 18.200, -67.120

A person was overtaken by a strong water current at the Concordia bridge, Trastalleres sector of Mayaguez but was rescued unharmed. Moderate to localized heavy showers and isolated thunderstorms affected the Western Interior and central area of Mayaguez.

Heavy Rain, Western Interior

When: May 2, 4:00 PM AST to 10:00 PM AST
Where: Western Interior County, 1.64 mi NNW of Utuado
Reported by: Emergency Manager
Coordinates: 18.293, -66.706

Emergency Managers reported mudslides and flooding over Arecibo and vicinity areas. Rivers Rio Grande de Arecibo and Rio Vivi were reported near flood stage. Small stream flooding was reported near Rivas Dominici Avenue, at Road 111 in front of Metropolitan Hospital. Road 123 at Barrio Abajo in Utuado was impassable due to a mudslide which caused the street to close in both directions.

Debris Flow, Northwest

When: May 2, 4:15 PM AST
Where: Northwest forecast zone
Property damage: $3,000
Reported by: Emergency Manager

Road 416, Km. 5.2 at Barrio Laguna in Aguada was blocked due to a mudslide. Other landslides were reported along road 402 at Barrio Caracol, and Highway 2 Interior at Quebrada Larga sector in the municipality of A asco.

Flash Flood, Western Interior

When: May 2, 4:28 PM AST to 6:00 PM AST
Where: Western Interior County, 4.17 mi NE of Lares
Cause: Heavy Rain
Property damage: $18,000
Reported by: Emergency Manager
Coordinates: 18.315, -66.828

An automobile and its driver were swept by swollen River Camuy along road 134, Km. 17.3, in the municipality of Utuado, at sector Las Lozas. The driver was found dead about two hours later.

Debris Flow, Western Interior

When: May 2, 4:38 PM AST
Where: Western Interior forecast zone
Reported by: Emergency Manager

A landslide was reported along road 10, Km. 27.1, at Barrio Portuguez in Adjuntas.

Heavy Rain, Western Interior

When: May 2, 4:57 PM AST to 7:00 PM AST
Where: Western Interior County, 1 mi SE of Utuado
Reported by: Emergency Manager
Coordinates: 18.260, -66.689

Road 111 in the municipality of Utuado was reported flooded by a small stream near the old Department of Justice building.

Debris Flow, Western Interior

When: May 2, 4:57 PM AST
Where: Western Interior forecast zone
Property damage: $2,000
Reported by: Emergency Manager

Road 111, Km. 2.5 at Barrio Caguana in the municipality of Utuado was closed due to a mudslide.

Debris Flow, Western Interior

When: May 2, 4:57 PM AST
Where: Western Interior forecast zone
Property damage: $5,000
Reported by: Emergency Manager

Road 123 at Barrio Abajo in the municipality of Utuado was closed due to a mudslide and a downed power line.

Debris Flow, Western Interior

When: May 2, 4:57 PM AST
Where: Western Interior forecast zone
Property damage: $2,000
Reported by: Emergency Manager

Road 140 at Barrio Caonillas in the municipality of Utuado was closed due to a mudslide.

Flash Flood, Western Interior

When: May 2, 5:44 PM AST to 7:00 PM AST
Where: Western Interior County, 3.63 mi ENE of San Sebastian to 3.62 mi ENE of San Sebastian
Cause: Heavy Rain
Property damage: $15,000
Reported by: Emergency Manager
Coordinates: 18.331, -66.916

An automobile and its two occupants were swept by a swollen small stream, as they tried to make a low water crossing along road 451, at Sector Abrahondo, in the municipality of San Sebastian. One occupant was able to escape unharmed from the flood waters, but the other one drowned.

Flood, Mayaguez and Vicinity

When: May 2, 11:32 PM AST to May 3, 2:30 AM AST
Where: Mayaguez and Vicinity County, 2.86 mi W of Moca to 2.87 mi W of Moca
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 18.379, -67.114

River Culebrinas was reported out of its banks at Barrio Coco in the municipality of Moca.

Debris Flow, Western Interior

When: May 3, 10:00 AM AST
Where: Western Interior forecast zone
Reported by: Emergency Manager

Several landslides were reported along various roads in the municipality of Utuado, at road 621, Cerro Gordo Sector; road 123, Sector 315 Rio Abajo Antigua 10; road 111; road 523 Barrio Arenas; road 610 Barrio Don Alonso; road 603, Barrio Guainico, Blanca Nieves sector.

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.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
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 2008 Every state in 2008 This day in weather history Warnings in Puerto Rico, May 2008

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 2026-09-24. Each event’s entry at NCEI: 108829, 142975, 108652, 108839, 108706, 108707, 110773, 108845, 110281, 110284, 110286, 110289, 110318, 110787, 110816.