---
title: "Manoa Valley Flood, October 30, 2004 (National Weather Service)"
url: https://stacklist.com/card/e7b4e527-68d7-4a47-8f4a-d2ce9f8352af
source_url: "https://www.weather.gov/hfo/ManoaFlood20041030"
stack: https://stacklist.com/c/home/stack/a8ff26ca-a6ab-4f22-a49f-03737c5c4a7b
summary: "The Manoa Valley flood of October 30, 2004 was caused by a stationary thunderstorm over southeast Oahu, triggered by an upper level low interacting with the Koolau Mountains. Extremely heavy rainfall in a short period caused Manoa Stream to overflow its banks, resulting in significant flooding impacts across the area."
tags: "flood, hawaii, weather-event, thunderstorm, heavy-rainfall, manoa-valley, tropical-weather"
key_entities: "National Weather Service (NWS) (organization), NOAA (organization), Manoa Valley (location), Oahu (location), Koolau Mountains (location), Manoa Stream (location), Hawaii (location), Manoa Valley Flood Oct 30 2004 (event), Upper Level Low (concept), Thunderstorm Development (concept)"
classification: "analysis"
content_hash: "sha256:4f2b4d05dfd9d4918af8b22f940f8c6139c24c853ef4fbdbe8356610b23e178b"
acp_version: "0.2"
token_counts_approximate: 1972
visibility: public
agent_accessible: true
status: "final"
---

# Manoa Valley Flood, October 30, 2004 (National Weather Service)

HOME FORECAST Local Graphical Aviation Marine Rivers and Lakes Hurricanes Severe Weather Fire Weather Sunrise/Sunset Long Range Forecasts Climate Prediction Space Weather PAST WEATHER Past Weather Astronomical Data Certified Weather Data SAFETY INFORMATION Wireless Emergency Alerts Weather-Ready Nation Brochures Cooperative Observers Daily Briefing Damage/Fatality/Injury Statistics Forecast Models GIS Data Portal NOAA Weather Radio Publications SKYWARN Storm Spotters StormReady TsunamiReady Service Change Notices EDUCATION NEWS SEARCH Search For NWS All NOAA ABOUT About NWS Organization For NWS Employees National Centers Careers Contact Us Glossary Social Media NWS Transformation Local forecast by "City, St" or ZIP code Sorry, the location you searched for was not found. Please try another search. Multiple locations were found. Please select one of the following: Location Help Impacts from Lowell to impact the islands through Tuesday Lowell is expected to bring various impacts to all islands through Tuesday. High surf will continue through Monday night. Flooding will be possible Tuesday, and there is the possibility for some tornadoes/waterspouts through Monday night. Hurricane force winds are expected for Kauai and Niihau, with tropical storm force winds for Oahu, through Monday night. Read More > Customize Your Weather.gov Enter Your City, ST or ZIP Code Remember Me Privacy Policy LOADING... --> Honolulu, HI Weather Forecast Office Manoa Valley Flood Oct 30, 2004 Weather.gov > Honolulu, HI > Manoa Valley Flood Oct 30, 2004 Current Hazards Dự báo và Bản đồ nguy hiểm - Tiếng Việt 预报和灾害地图 - 中文 Tala o le Tau ma Ata o Fa'afanua o Tulaga Lamatia - Samoan Mapa de Pronósticos y Riesgos - Español Carte des prévisions et des dangers - Français Forecast and Hazards Map - English Hawaii Hazards Tropical Cyclones Tsunami Earthquake National Hazards Current Conditions Observations Satellite Hydrology Analyses/Forecast Charts Radar Local Kauai (PHKI) Standard Radar (low bandwidth) Local Kauai (PHKI) Enhanced Radar Local Molokai (PHMO) Standard Radar (low bandwidth) Local Molokai (PHMO) Enhanced Radar Local Kohala (PHKM) Standard Radar (low bandwidth) Local Kohala (PHKM) Enhanced Radar Local South Point (PHWA) Standard Radar (low bandwidth) Local South Point (PHWA) Enhanced Radar Regional Standard Radar (low bandwidth) Latest Radar Status Messages Hawaii Radars Forecasts Hawaii Aviation Activity Planner Marine Fire Weather Local Graphics High Seas Graphics National Graphics Model Output Rivers and Lakes New National Water Prediction Service (NWPS) Climate and Past Weather Local National Hawaii Climate Portal Tropical Cyclone Reports Local Programs Weather Radio Weather & Safety Tsunami Information Frequently Asked Questions Event Summaries Weather in Hawaii Turn Around, Don't Drown SkyWarn Spotters StormReady TsunamiReady Our Mission Our Office Our Products News Items News Archive HI RSS Feeds Widgets An upper level low lingering near the islands ( water vapor satellite image ) for days had made the atmosphere unstable, resulting in the development of heavy showers and thunderstorms around the islands. A small core of strong winds high in the atmosphere rotated around this upper level low during the day, helping to make the atmosphere near Oahu more unstable. During the late afternoon an area of showers being pushed west by the low level tradewind flow interacted with the Koolau Mountains on the windward (east) side of Oahu. As the air was pushed up over the mountains, the unstable environment allowed those showers to rapidly develop into a thunderstorm and remain focused over a small area of southeast Oahu ( infrared satellite image ). This thunderstorm, locked into place due to the terrain, produced very heavy rainfall totals in just a few hours ( radar loop ). The focus of the heaviest rain occurred over the southern portion of the Koolau Mountains on Oahu, resulting in Manoa Stream overflowing its banks and causing significant flooding in Manoa Valley, including the University of Hawaii campus. At the height of the heavy rainfall ( radar ) around 7 pm, rainfall rates recorded at the gauge at the Manoa Lyon Arboretum, in the upper portion of Manoa Valley, were over 5 inches per hour. Here are some maximum rainfall accumulations at that site: 15min: 1.29 inches 1-hr: 3.72 inches 2-hr: 4.38 inches 3-hr: 5.73 inches 6-hr: 8.71 inches   These large rainfall rates are estimated to occur with a return rate of almost 50 years. In other words, in any given year, there is only a 2% probability of such a heavy rainfall event like this occurring in upper Manoa Valley. A stream gage operated by the US Geological Survey on Waiakeakua Stream, a tributary of Manoa Stream, detected a surge in flow between 6:45 pm and 7:40 pm in response to the peak rainfall. Rainfall Totals Click for a map showing 24 hour rainfall totals across Oahu Click for a map showing Doppler radar estimated rainfall   Rainfall Totals (in inches) for selected locations across Southeast Oahu for the 12 hour period between 2pm October 30 and 2am October 31. Manoa Lyon Arboretum 10.07 Wilson Tunnel 6.84 Luluku 6.47 Saint Stephens 4.68 Alewa Heights 4.45 Maunawili 3.41 Ahuimanu Loop 2.31 Palolo 2.12 Moanalua 1.69 Olomana 1.05 Aloha Tower Downtown Honolulu 0.34 Honolulu Airport 0.12 Damage Reports Significant damage occurred in Manoa Valley and on the University of Hawaii campus due to Manoa Stream overflowing its banks. The National Weather Service Office is located on the University of Hawaii campus, and although no damage occurred to the facility, two to three feet of water flowed through the parking lot and around the building in which the office is located, depositing mud and debris. Following are some pictures taken by staff members of damage on the University of Hawaii campus and elsewhere in Manoa Valley Cars pushed by the floodwaters adjacent to Manoa Stream, Manoa Valley Small footbridge over Manoa Stream, Manoa Valley Debris on bridge over Manoa Stream, Manoa Valley Vehicles parked by the Weather Service Office, University of Hawaii Outside of Hamilton Library, University of Hawaii National Weather Service Warnings Urban and Small Stream Flood Advisory - 355 pm Flash Flood Warning - 631 pm (about 75 minutes before flooding began) Short Term Forecast - 658 pm Flash Flood Warning - 722 pm Flash Flood Statement - 759 pm (includes first reports of flooding) Flash Flood Statement - 837 pm (includes reports of flooding beginning on UH campus) Short Term Forecast - 847 pm Flash Flood Statement - 900 pm (reports of 2 feet of water by NWS office) Flash Flood Statement - 1000 pm (canceling the warning) Initial Storm Reports - 1112 pm --> --> -->   Follow us on X   Follow us on Facebook   Follow us on YouTube   HFO RSS Feed --> --> Current Hazards Hawaii Hazards Tropical Cyclones Tsunami Earthquake National Hazards Current Conditions Satellite Observations Analyses/Forecast Charts Hydrology Radar Kauai (PHKI) South Point (PHWA) Hawaii Radar Kohala (PHKM) Molokai (PHMO) Forecasts Model Output Fire Weather National Graphics Aviation Local Graphics Marine Activity Planner Hawaii Climate and Past Weather Local National Hawaii Climate Portal Tropical Cyclone Reports Local Programs News Archive Weather Radio Weather and Safety Tsunami Safety Weather in Hawaii Frequently Asked Questions Event Summaries Turn Around, Don't Drown StormReady TsunamiReady Our Mission Our Office Our Products HI RSS Feeds --> US Dept of Commerce National Oceanic and Atmospheric Administration National Weather Service Honolulu, HI 2525 Correa Rd Suite 250 Honolulu, HI 96822 (808) 973-5286 Comments? 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