Puerto Rico, 2008Flash Flood and Debris Flows in Puerto Rico, September 1 to 3, 2008
September 1 to 3, 2008 · NWS SJU · 20 events in 8 counties and zones
The extreme outer bands of Tropical Storm Hanna impacted Puerto Rio during the first week of September. Hanna's circulation induced a low level flow of south to southwest winds that pushed showers and thunderstorms from the Caribbean waters northward into the island.
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
- Deaths
- 2
- Injuries
- 0
- Property damage
- $73,000
- Crop damage
- None recorded
- Events
- 20
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.
The extreme outer bands of Tropical Storm Hanna impacted Puerto Rio during the first week of September. Hanna's circulation induced a low level flow of south to southwest winds that pushed showers and thunderstorms from the Caribbean waters northward into the island. Rainfall amounts of 10-12 inches were recorded in some areas over a 24 hour period ending on Wednesday September 3. Many rivers were reported out of their banks, numerous landslides were reported. Flooded streets and closed roads, strong gusty winds and isolated tornadoes were also registered. People were put in shelters along the western municipality of Anasco due to flooding. Hanna's center, at its closest point to Puerto Rico on September 3, 2008, the day when the islands were most affected by the storm, was nearly 350 miles away to the west northwest.
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 Sep 1, 11:45 AM AST, 2 hours 15 minutes earlier.
Area forecast discussion, Sep 1, 11:45 AM AST, 2 hours 15 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1145 AM AST MON SEP 1 2008
.UPDATE...MILD S TO SE FLOW HAS DAMMED SHOWERS ALONG THE SRN
SLOPES OF S AND E PR THIS MORNING...WHILE EN ENE FLOW BUILDING
INTO THE EXTREME NE CARIB IS INDUCING LLVL CONVERGENCE ACROSS THE
VIRGIN ISLANDS AND OPEN NE CARIB AND UPSTREAM INTO THE LEEWARDS.
LIGHT AND VEERING WINDS IN THE LOWER TROP ARE EXPECTED TO YIELD
SLOW MOVING CNVTV CELLS TODAY...WHICH COULD LEAD TO SIGNIFICANT
RAIN ACCUMULATIONS...AND SOME FLOODING IS TO BE EXPECTED TODAY.
THIS IS IN LINE WITH PREVIOUS SYNOPTIC REASONING...AND ONLY MINOR
ALTERATIONS TO FORECAST HAVE BEEN MADE.
&&
.DISCUSSION...
&&
.PREV DISCUSSION... /ISSUED 531 AM AST MON SEP 1 2008/
SYNOPSIS...A LARGE HIGH PRESSURE IS OVER THE GULF OF MEXICO WITH
A WEAKER HIGH OVER PUERTO RICO. DURING THE WEEK PUERTO RICO PASSES
THROUGH A SADDLE BACK UNTIL HIGH PRESSURE MOVES INTO THE WESTERN
ATLANTIC FRIDAY AND SATURDAY. ON SUNDAY A WEAK LOW MOVES INTO THE
AREA FROM THE EAST.
AT MID LEVELS...TROPICAL STORM HANNA REMAINS JUST NORTH OF THE
BAHAMAS THROUGH THURSDAY. ON WEDNESDAY HIGH PRESSURE BEGINS
BUILDING IN OVER THE CARIBBEAN FROM THE CENTRAL ATLANTIC. SUCH
THAT BY FRIDAY EVENING IT IS NEAR 30 DEGREES NORTH LATITUDE...DUE
NORTH OF PUERTO RICO. THIS HIGH RETURNS TO THE CENTRAL ATLANTIC BY
MID WEEK NEXT WEEK. AFTER THURSDAY...DRIER AIR PREVAILS.
AT LOWER LEVELS...TROPICAL STORM HANNA IS STILL VIGOROUS AND
MOVING VERY SLOWLY TO THE WEST. SHE WILL REMAIN SUFFICIENTLY CLOSE
TO INFLUENCE THE CIRCULATION AT LOWER LEVELS UNTIL THURSDAY. ON
FRIDAY A TROPICAL WAVE WILL MOVE THROUGH THE AREA FROM ITS CURRENT
POSITION AT 39 WEST...THOUGH TIMING MAY CHANGE IF IT DEVELOPS.
OTHER CIRCULATIONS FOLLOW BUT MOVE NORTHWEST BEFORE REACHING THE
LOCAL AREA.
DISCUSSION...HANNA IS GRADUALLY EDGING TO THE WEST BUT STILL
PULLING IN A WIDE SWATH OF AIR FROM THE SOUTH OVER PUERTO RICO AND
THE U.S VIRGIN ISLANDS. THIS AIR IS ONLY SOMEWHAT UNSTABLE...BUT
WITH LESS CLOUDS...AND THEREFORE BETTER HEATING...DAYTIME CONVECTION
OVER THE LOCAL AREA...AT LEAST OVER PUERTO RICO...HAS BEEN SHOWING
AN INCREASING TREND AND THE FORECAST TODAY CONTINUES IN THAT VEIN.
ALSO A BAND OF CONVECTION...OR AT LEAST BETTER MOISTURE...IS MOVING
INTO THE AREA FROM THE NORTHEAST TONIGHT. BOTH MODELS THEN SHOW A
BAND OF SHOWERS FORMING OVER OR JUST NORTHEAST OF THE U.S. VIRGIN
ISLANDS AND A GOOD ENHANCEMENT OF THE SHOWER ACTIVITY FOR THE
SAME. LOW LEVEL CIRCULATION...IN THE MEANTIME...FROM 700 MB
DOWNWARD WEAKENS...MARKING THE ZONE OF SEPARATION FROM THE
CIRCULATION OF HANNA. NEVERTHELESS LIGHT SOUTHERLY FLOW CONTINUES
THROUGH THURSDAY SEEMINGLY UNAFFECTED BY ANY OTHER FEATURES. AFTER
WEDNESDAY...LOWER LEVELS SHOW A DISTINCTIVE DRYING THAT IS LIKELY
TO LEAD TO LESS SHOWER ACTIVITY AND WARMER TEMPERATURES
EVERYWHERE. IT IS SHORTLY INTERRUPTED HOWEVER...WHEN A TROPICAL
WAVE...NOW MANIFESTING ITSELF AS A CANDIDATE FOR TROPICAL STORM
DEVELOPMENT...MOVES THROUGH THE AREA ON FRIDAY WITH CONSIDERABLE
MOISTURE. WOULD EXPECT THIS SCENARIO TO CHANGE SIGNIFICANTLY
SHOULD THE SYSTEM DEVELOP INTO A TROPICAL STORM. AT THIS
TIME...HOWEVER...EVEN IF IT SHOULD DEVELOP...IT IS NOT EXPECTED TO
THREATEN PUERTO RICO OR THE U.S. VIRGIN ISLANDS WITH MORE THAN
INCREASED SHOWER AND THUNDERSTORM ACTIVITY.
AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS MOST TAF SITES DURING
THE MORNING HOURS. BRIEF PERIODS OF MVFR CONDITIONS ARE POSSIBLE
ACROSS TJPS...TIST...AND TISX AT LEAST THROUGH 14Z AS SCATTERED
SHOWERS MOVE BY THESE AREAS. LATEST TJSJ 00Z SOUNDING INDICATED A
VERY LIGHT AND VARIABLY WIND FLOW FROM THE SURFACE TO AROUND 40K
FEET. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP OVER CENTRAL
PUERTO RICO AFTER 17Z PRODUCING MOUNTAIN OBSCURATIONS AND
VISIBILITIES LOCALLY BELOW 3 SM.
MARINE...SEAS FROM HANNA HAVE RISEN TO ABOVE 8 FEET AGAIN THIS
MORNING...CREATING A CONSIDERABLE GRADIENT OF SEA HEIGHTS ACROSS
THE LOCAL WATERS. SEAS OF 6 FEET ARE EXPECTED TO PERSIST THROUGH
TUESDAY IN THE NORTHERN REACHES OF OUR ATLANTIC OFFSHORE WATERS.
HANNA IS HAVING LITTLE EFFECT IN THE CARIBBEAN. AFTER TUESDAY SEAS
SUBSIDE SLOWLY IN THE ATLANTIC. SEAS REMAIN RELATIVELY TRANQUIL IN
THE CARIBBEAN THROUGH THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 90 78 / 50 20 20 10
STT 88 79 87 79 / 50 70 70 30
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
70/99
Hazardous weather outlook, Sep 1, 6:16 AM AST, 7 hours 44 minutes before
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
616 AM AST MON SEP 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-
616 AM AST MON SEP 1 2008
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE
ADJACENT COASTAL WATERS.
.DAY ONE...TODAY AND TONIGHT
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED.
AMZ720-730-VIZ001-002-021030-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
616 AM AST MON SEP 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 AT THIS TIME.
.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED.
Event by event
9 flood, 6 debris flow, 2 thunderstorm wind, 1 flash flood, 1 funnel cloud, 1 high surf. Local standard time, as filed.
Flash Flood, Northeast
- When
- September 1, 2:00 PM AST to 2:30 PM AST
- Where
- Northeast County, 4.63 mi NW of Naguabo to 4.58 mi NW of Naguabo
- Cause
- Heavy Rain
- Deaths
- 2 direct, 0 indirect
- Reported by
- Newspaper
- Coordinates
- 18.262, -65.785
A flash flood overtook a group of four hikers as they were walking along the banks of River Prieto-River Blanco along the south slope of the Caribbean National Forest El Yunque in the municipality of Naguabo. Two of the hikers were able to escape the flash flood, the other two were washed by the water surge. Showers affected the rain forest during the early afternoon causing rainfall amounts of around 1.5 inches.
Debris Flow, Mayaguez and Vicinity
- When
- September 3, 3:00 AM AST
- Where
- Mayaguez and Vicinity forecast zone
- Reported by
- Emergency Manager
A landslide was reported at Barrio Duey Abajo, in San German.
Flood, Southwest
- When
- September 3, 6:59 AM AST to 10:00 AM AST
- Where
- Southwest County, 3.16 mi NW of Cabo Rojo to 3.15 mi NW of Cabo Rojo
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 18.066, -67.159
Flooding was reported at Parcelas Pedernales in Cabo Rojo.
Flood, Northeast
- When
- September 3, 7:55 AM AST to 11:00 AM AST
- Where
- Northeast County, 2.4 mi NE of Rio Grande to 2.43 mi NE of Rio Grande
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 18.372, -65.772
Flooding was reported at Barrio Palmer along road 191 in the municipality of Rio Grande.
Flood, Southwest
- When
- September 3, 9:47 AM AST to 12:45 PM AST
- Where
- Southwest County, 4.76 mi ENE of Lajas to 4.71 mi ENE of Lajas
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 18.037, -66.969
Flooding was reported at Barrio Rayo Plata in the municipality of Lajas.
Flood, Central Interior
- When
- September 3, 10:34 AM AST to 1:30 PM AST
- Where
- Central Interior County, 2.89 mi W of Jayuya to 2.88 mi W of Jayuya
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 18.195, -66.624
Flooding was reported at Barrio Jauca, Sector Montaner, in Aibonito.
Debris Flow, Western Interior
- When
- September 3, 10:40 AM AST
- Where
- Western Interior forecast zone
- Reported by
- Emergency Manager
A landslide was reported at Barrio Pica, St 369 Km 1-H4 in the municipality of Sabana Grande.
Thunderstorm Wind, Eastern Interior
- When
- September 3, 10:50 AM AST
- Where
- Eastern Interior County, 2.88 mi SW of Caguas to 2.61 mi SW of Caguas
- Measured
- 35 kt (40 mph) estimated gust
- Property damage
- $25,000
- Reported by
- Public
- Coordinates
- 18.171, -66.061
Strong gusty winds were reported in the vicinity of Guavate near the border of Barrio Borinquen with Caguas and Cayey Cities. Several downed power lines were reported along road 763.
Debris Flow, Eastern Interior
- When
- September 3, 10:54 AM AST
- Where
- Eastern Interior forecast zone
- Reported by
- Emergency Manager
Emergency Management officials reported a landslide at Bo Ceiba Sur, in the municipality of Juncos.
Flood, Southwest
- When
- September 3, 11:18 AM AST to 2:00 PM AST
- Where
- Southwest County, 4.55 mi ENE of Lajas to 4.56 mi ENE of Lajas
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 18.035, -66.972
Flooding was reported along road 117 at Barrio La Plata in the municipality of Lajas.
Funnel Cloud, Eastern Interior
- When
- September 3, 11:30 AM AST to 11:40 AM AST
- Where
- Eastern Interior County, 2.67 mi WNW of Caguas to 2.46 mi WNW of Caguas
- Reported by
- Public
- Coordinates
- 18.209, -66.070
Three funnel clouds were reported by a resident of Villa del Rey neighborhood in Caguas City.
Flood, Mayaguez and Vicinity
- When
- September 3, 11:55 AM AST to 3:00 PM AST
- Where
- Mayaguez and Vicinity County, 2.5 mi SE of San German to 2.59 mi SE of San German
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 18.079, -66.999
Emergency Management reported flooding at Barrio Minillas, road 102 in the municipality of San German.
Flood, North Central
- When
- September 3, 12:45 PM AST to 4:45 PM AST
- Where
- North Central County, 1.4 mi SW of Vega Alta to 1.47 mi SW of Vega Alta
- Cause
- Heavy Rain
- Reported by
- Emergency Manager
- Coordinates
- 18.405, -66.344
River Cibuco was reported flooding road 620 in Vega Alta.
Debris Flow, Western Interior
- When
- September 3, 3:50 PM AST
- Where
- Western Interior forecast zone
- Reported by
- Emergency Manager
Emergency Management officials reported a landslide near Calle del Agua #62 in the municipality of Adjuntas.
High Surf, Ponce and Vicinity
- When
- September 3, 3:59 PM AST
- Where
- Ponce and Vicinity forecast zone
- Reported by
- Broadcast Media
A pier piling was reported damaged at the Ponce Nautical Club.
Thunderstorm Wind, Eastern Interior
- When
- September 3, 3:59 PM AST
- Where
- Eastern Interior County, 0.41 mi WNW of Comerio
- Measured
- 39 kt (45 mph) estimated gust
- Property damage
- $15,000
- Reported by
- Broadcast Media
- Coordinates
- 18.223, -66.225
Downed power lines were reported in Comerio municipality.
Flood, Mayaguez and Vicinity
- When
- September 3, 4:15 PM AST
- Where
- Mayaguez and Vicinity County, 0.35 mi SW of Anasco to 0.54 mi SSE of Anasco
- Cause
- Heavy Rain
- Reported by
- Emergency Manager
- Coordinates
- 18.277, -67.124
Six homes were reported flooded in Barrio Espino of Anasco municipality.
Debris Flow, Eastern Interior
- When
- September 3, 4:57 PM AST
- Where
- Eastern Interior forecast zone
- Property damage
- $3,000
- Reported by
- Emergency Manager
Emergency Management officials reported a landslide at Bo. Barrancas, Road 771, km 7.9 in the municipality of Barranquitas.
Debris Flow, Eastern Interior
- When
- September 3, 5:00 PM AST
- Where
- Eastern Interior forecast zone
- Reported by
- Emergency Manager
Emergency Management officials reported a landslide at Bo. Helecho, road # 143, km 58.2 in the municipality of Barranquitas.
Flood, Northeast
- When
- September 3, 5:41 PM AST
- Where
- Northeast County, 2.87 mi NE of Rio Grande to 2.88 mi NE of Rio Grande
- Cause
- Heavy Rain
- Reported by
- Broadcast Media
- Coordinates
- 18.373, -65.764
The Westin Rio Mar Hotel Golf course was reported flooded. River Mameyes was also out of its banks.
- 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.
- Flood
- Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
- Funnel Cloud
- A rotating column of cloud extending from a thunderstorm that did not reach the ground.
- High Surf
- Large waves breaking on the shore that caused damage, erosion or casualties.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Hurricane and Tornadoes in Louisiana, September 1 to 3, 20086 deaths · 2 injured · $951 million · EF2 · 32 events
- Hurricane and Tornadoes in Louisiana, September 1 to 2, 20083 deaths · $151 million · EF1 · 42 events
- Tropical Storm and Flash Flooding in Louisiana, September 1 to 3, 20081 death · 7 injured · $14 million · 30 events
- Tornadoes and Tropical Storm in Mississippi, September 1 to 4, 2008$71 million · EF1 · 70 events
- Tornadoes and Tropical Storm in Louisiana, September 1 to 3, 2008$386 million · EF1 · 25 events
- Tornado and Tropical Storm in Arkansas, September 1 to 3, 2008$41 million · EF0 · 5 events
- Hurricane and Storm Surge in Mississippi, September 1 to 2, 2008$22 million · 11 events
- Storm Surge in Alabama, September 1, 2008$4.5 million · 3 events
- Storm Surge in Florida, September 1 to 2, 2008$1.0 million · 5 events
- Storm Surge in Florida, September 1, 2008$550,000 · 3 events
- Flash Flooding in Alabama, September 1, 2008$259,000 · 3 events
- Tornadoes in Florida, September 1, 2008$37,000 · EF0 · 7 events
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: 125967, 135283, 135381, 135389, 135950, 136402, 136456, 137112, 136748, 136457, 137110, 136474, 137114, 136749, 134527, 137115, 134523, 136750, 136751, 134526.