Flash Flood, Hawaii
- When
- April 12, 7:45 AM HST to 4:30 PM HST
- Where
- Hawaii County, 9 mi WNW of Honokaa
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 19.602, -155.523 (the zone’s center; the record gives no point)
Flash Flood in Hawaii, April 12, 2004
Heavy showers and rain, that exceeded 11 inches in a 24-hour period over some parts of the windward section of the Big Island of Hawaii, were associated with a stationary shear line. The deluge forced the closure of several roads from Waipio Valley to upslope areas in the Puna District.
Where it happened
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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 HFO wrote it up.
Heavy showers and rain, that exceeded 11 inches in a 24-hour period over some parts of the windward section of the Big Island of Hawaii, were associated with a stationary shear line. The deluge forced the closure of several roads from Waipio Valley to upslope areas in the Puna District. The rain also triggered landslides that halted traffic on other streets and roadways. The cost of damages was not available. No serious injuries were reported.
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 Honolulu, HI wrote its last area forecast discussion before the first event at Apr 12, 4:04 AM HST, 3 hours 41 minutes earlier.
Area forecast discussion, Apr 12, 4:04 AM HST, 3 hours 41 minutes before
NARRATIVE SYNOPTIC DISCUSSION FOR AMERICAN SAMOA AND THE INDEPENDENT STATE OF SAMOA TODAY AND TUESDAY... MOST OF THE LAYERED CLOUDS HAVE MOVED WEST OF SAMOA WITH VERY ISOLATED CONVECTION REMAINING OVER THE REGION AND UPSTREAM TO THE EAST. THE LOW LEVEL FLOW OVER THE REGION REMAINS RATHER COMPLEX WITH A LOW EAST OF SAMOA AND A TROUGH EXTENDING INTO A COL AREA OVER SAMOA. GRADUALLY, LIGHT SOUTHEAST WINDS WILL BUILD IN OVER SAMOA LATER TODAY AND TONIGHT. MODELS INDICATE SUFFICIENT MOISTURE AND INSTABILITY OVER THE AREA SO SHOWERS AND A CHANCE OF HEAVY SHOWERS OR THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH TUESDAY. THE SOUTHERLY SWELL AROUND 3 OR 4 FEET WILL CONTINUE THROUGH TOMORROW. OUTLOOK FOR WEDNESDAY THROUGH FRIDAY... A WEAK SURFACE RIDGE SETS UP OVER THE REGION AND SHOULD LEAVE SAMOA UNDER LIGHT NORTHEAST WINDS WEDNESDAY, TURNING NORTH THEN NORTHWEST THURSDAY AND FRIDAY. NO ORGANIZED PRECIPITATION EVENTS ARE EXPECTED, JUST RANDOM PASSING SHOWERS THROUGH THE PERIOD. THE MAIN CONVERGENCE AREA WILL REMAIN SOUTHWEST OF SAMOA. NARRATIVE DISCUSSION FOR TUVALU TODAY AND WEDNESDAY...TUVALU TIME... A TROPICAL DISTURBANCE REMAINS ABOUT 350 MILES SOUTH OF TUVALU THIS MORNING WITH TROUGHS EXTENDING NORTHWEST AND SOUTHEAST OF THE SYSTEM. A BROAD RIDGE REMAINS OVER TUVALU WITH LIGHT NORTHEAST WINDS OVER THE AREA. THE RIDGE WILL SHARPEN TONIGHT WITH THE AXIS SOUTH OF TUVALU AND WINDS BECOMING MORE EASTERLY BUT STILL 10 KNOTS OR LESS. ISOLATED HEAVY SHOWERS AND POSSIBLE THUNDERSTORMS JUST EAST OF THE DATELINE AT THIS TIME WILL BE MOVING ACROSS TUVALU DURING THE DAY TODAY. MOST OF THE CONVERGENCE IN THE REGION WILL REMAIN SOUTH OF TUVALU THROUGH WEDNESDAY SO TODAY MIGHT BE THE MOST ACTIVE WEATHER DAY AS THE SHOWERS EAST OF THE DATELINE MOVE THROUGH. EFFECTIVE MAY 26...2004 AT 1800 UTC...THE NATIONAL WEATHER SERVICE OFFICE IN HONOLULU WILL NO LONGER ISSUE THIS DISCUSSION. THE NATIONAL WEATHER SERVICE IN PAGO PAGO WILL BEGIN ISSUING THIS PRODUCT ON MAY 26...2004.
The radar
The national radar mosaic for the moment the first event began.
Event by event
1 flash flood. Local standard time, as filed.
What these are
- 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
- High Wind and Strong Wind in Florida, April 12, 2004
- Tornado in Florida, April 12, 2004
- Hail and Damaging Winds in Alabama, April 12, 2004
- Tornado and Damaging Winds in Florida, April 12, 2004
- Heavy Rain in New Jersey, April 12 to 13, 2004
- Hail and Damaging Winds in Georgia, April 12, 2004
- Lightning Strike in Florida, April 12, 2004
- Flooding in West Virginia, April 12 to 14, 2004
- Heavy Rain in Maryland, April 12 to 13, 2004
- Hail and Damaging Winds in Florida, April 12, 2004
- Marine Thunderstorm Winds in Gulf of Mexico, April 12, 2004
- Marine Thunderstorm Winds in Gulf of Mexico, April 12, 2004
More
Every storm in Hawaii in 2004Every state in 2004This day in weather historyWarnings in Hawaii, April 2004
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: 5431530.