Flash Flood, Hawaii
- When
- August 3, 4:40 AM HST to 12:20 PM HST
- Where
- Hawaii County, 16 mi NE of Kailua Kona
- Reported by
- NEWSPAPER
- Coordinates
- 19.602, -155.523 (the zone’s center; the record gives no point)
Flash Flood in Hawaii, August 3, 2004
The combination of an upper trough and remnants from Hurricane Darby resulted in heavy showers and thunderstorms impacting the lee side of the Big Island of Hawaii. Excessive runoff forced the closure of 5 schools, where some classrooms were flooded.
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.
The combination of an upper trough and remnants from Hurricane Darby resulted in heavy showers and thunderstorms impacting the lee side of the Big Island of Hawaii. Excessive runoff forced the closure of 5 schools, where some classrooms were flooded. The flash flooding also closed several roads for a time because of rock slides and deep ponding. Estimates of damages were 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 Aug 3, 4:00 AM HST, 40 minutes earlier.
Area forecast discussion, Aug 3, 4:00 AM HST, 40 minutes before
HAWAIIAN ISLANDS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 400 AM HST TUE AUG 3 2004 .SYNOPSIS... A FLASH FLOOD WATCH REMAINS IN EFFECT TODAY FOR THE ENTIRE STATE. THE REMNANT LOW OF TROPICAL STORM DARBY...CENTERED 25 MILES EAST OF HANA...IS BRINGING HEAVY SHOWERS AND ISOLATED THUNDERSTORMS TO THE BIG ISLAND AND MAUI. EXPECT SHOWERS...WITH SOME ANCHORED HEAVY SHOWERS THAT MAY CAUSE FLASH FLOODING...TODAY...SPREADING WESTWARD TO THE OTHER ISLANDS. TRADE WINDS CONTINUE OVER THE SMALLER ISLANDS...BUT WILL BECOME VARIABLE AS THE LOW CONTINUES WESTWARD AT LESS THAN 10 MILES PER HOUR. && .DISCUSSION... EX-DARBY...APPARENTLY STILL A CLOSED SURFACE LOW...WAS ABOUT 25 MILES EAST OF HANA AT 200 AM THIS MORNING. A WIDE SHIELD OF DEEP TROPICAL MOISTURE...WITH EMBEDDED HEAVY SHOWERS AND ISOLATED THUNDERSTORMS SURROUNDS THIS CENTER AND WILL BE AFFECTING ALL THE MAIN HAWAIIAN ISLANDS TODAY INTO WEDNESDAY. HEAVY SHOWERS ARE OCCURRING MAINLY ON MAUI AND THE BIG ISLAND...AND A FLASH FLOOD WATCH IS IN EFFECT FOR THE ENTIRE STATE THROUGH 4 PM TODAY. HEAVY SHOWERS...SOME OF WHICH MAY BECOME ANCHORED...MAY PRODUCE FLASH FLOODING STATE-WIDE TODAY. A 1034 MB HIGH FAR NORTH OF THE STATE WILL KEEP TRADE WINDS OVER THE SMALLER ISLANDS TODAY...BUT WINDS WILL BE AFFECTED BY A WEAK CYCLONIC CIRCULATION AROUND A SURFACE LOW THAT REMAINS FROM TROPICAL STORM DARBY. WINDS ON THE BIG ISLAND OF HAWAII ARE ALREADY LIGHT SOUTHERLY DUE TO THE PROXIMITY OF THIS LOW. AN UPPER LEVEL TROUGH OF LOW PRESSURE JUST WEST OF KAUAI IS HELPING PRODUCE THE HEAVY SHOWERS BY DESTABILIZING THE WARM HUMID AIR WITHIN THE TROPICAL LOW CIRCULATION. THIS INSTABILITY IS EVIDENT ON BOTH THE LIHUE AND HILO SOUNDINGS. A K-INDEX OF 37...WITH A LIFTED INDEX OF -4.1 INDICATES A VERY UNSTABLE ATMOSPHERE OVER THE BIG ISLAND AND WITHIN THE CIRCULATION OF THE REMNANT LOW NEAR MAUI. MODELS ARE KEEPING WINDS SOUTHEASTERLY ON WEDNESDAY...AT THE REMNANT LOW MOVES BY KAUAI...AND THE HEAVY RAINS SHOULD BECOME MORE LIMITED... MAINLY TO KAUAI AND OAHU. BY THURSDAY OUR MORE NORMAL TRADE WINDS WILL RETURN...ALONG WITH DRIER AND MORE STABLE WEATHER. && .LONG TERM... WE ARE ALSO WATCHING ANOTHER AREA OF THREATENING WEATHER...TROPICAL DEPRESSION SIX-E...LESS THAN 1600 MILES EAST SOUTHEAST OF HILO. THE NATIONAL HURRICANE CENTER IN MIAMI HAS REDUCED THE CHANCES OF THIS SYSTEM DEVELOPING...BUT THE AVIATION MODEL IS STILL BRINGING A LARGE SLUG OF TROPICAL MOISTURE OVER THE STATE LATE FRIDAY INTO SATURDAY. THUS...HEAVY RAINFALL IS AGAIN A POSSIBLITY FOR THE COMING WEEKEND. && .HFO WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH ALL ISLANDS. && FARRELL
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
- Tornadoes and Flash Flooding in Iowa, August 3 to 4, 2004
- Flash Flooding and Hail in Wisconsin, August 3, 2004
- Hurricane and Flash Flooding in North Carolina, August 3, 2004
- Damaging Wind in Minnesota, August 3, 2004
- Damaging Wind in South Dakota, August 3, 2004
- Damaging Wind in Minnesota, August 3, 2004
- Damaging Wind in Minnesota, August 3, 2004
- Damaging Winds and Lightning Strike in Iowa, August 3, 2004
- Damaging Wind in South Dakota, August 3, 2004
- Hail and Damaging Winds in Iowa, August 3, 2004
- Lightning Strike in Maine, August 3, 2004
- Damaging Wind in New York, August 3, 2004
More
Every storm in Hawaii in 2004Every state in 2004This day in weather historyWarnings in Hawaii, August 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: 5431586.