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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 2— Management of the Disaster Event EMERGENCY WARNING PROCEDURES When National Weather Service (NWS) meteorologists believe that current weather conditions could produce potential flooding, they can issue either a flash flood watch or a flash flood warning. These terms have special meanings and provide the basis for emergency management agencies to take specific predetermined actions. A flash flood watch is issued by NWS to the locally designated emergency management agency, which is to coordinate all disaster response efforts when the NWS has reason to believe that flash floods may pose a threat to life and property. In Oahu the designated agency is the Oahu Civil Defense Agency (OCDA). When OCDA receives such a message, its personnel alert relevant OCDA staff and other relevant city, county, and state agencies of the possibility of flooding. These agencies are identified in OCDA's Standard Operating Procedures for a Flash Flood. In effect, this puts relevant public agencies on a stand-by status, making them aware that they should be ready to mobilize their equipment and personnel quickly. However, OCDA's emergency operations center (EOC) is not activated by a watch message; that is, representatives from these agencies are not brought to one location at this time. The function of the EOC is to centralize information resources and decision making. A flash flood warning message from the NWS indicates that dangerous flooding is expected or is occurring and that residents should take necessary actions immediately. When OCDA receives such a message, its EOC is fully activated and additional agency and organizational representatives are brought in to enhance decision making and resource allocation. The EOC, in effect, becomes the command post for responding to the impending disaster.
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 THE PREDISASTER PERIOD Beginning at 8:00 p.m. on December 31, 1987, when the NWS in Honolulu bypassed a flood watch step and issued a flood warning for the eastern part of Oahu, few of its residents realized that a natural disaster was in the making. When the torrential rainfall finally subsided the next morning, the residents of Oahu were confronted with more than $34 million in flood damages (Interagency Flood Hazard Mitigation Team, 1988). The major disaster areas were in the valleys of Niu, Kuliouou, and Hahaione, in the southeastern part of Oahu, and the Waimanalo area and Coconut Grove (Kailua) on the windward side of the Koolau Mountains (Figure 1). Although the total amount of damage may not be considered severe by continental U.S. standards and no lives were lost, the alarming aspect of the event was that the flood occurred without warning and affected densely populated urban watershed areas. For the island of Oahu, 1987 had been a very dry year. Until December 11, only 6.27 inches of rain had been recorded at Honolulu International Airport; the normal rainfall to that date was 21.25 inches. Then, beginning on December 12, a 10-day storm dropped an average of 12 inches of rain on the island, with the raingauge at Honolulu Airport measuring a 10-day high of 14.76 inches. Within one 24-hour period on December 12, as much as 6 inches of rain fell. Throughout this 10-day (December 12–21) period, the NWS issued several flash flood advisories and watches as well as advisories and watches for high winds and high surf. This mid-December storm was accompanied by a wide variety of flood-related problems. In conjunction with the NWS flash flood warning on December 12, minor flooding occurred in Kalihi, Kalihi Valley, Kaneohe, Waikiki, Kahala, Aina Haina, and Waimanalo. Five thousand customers in 73 different areas of the island lost telephone service due to weather-related problems. By December 16, 3,000 customers were still without phone service, including the federal building in Honolulu. In addition, scattered water mains broke, power outages occurred, and fallen boulders and trees blocked roadways and damaged property. Evacuation centers were readied to admit people who might have had to evacuate their homes if the flood problems worsened; however, none needed to be opened. A spokesperson for the OCDA referred to the December 12–20 event as a ''nuisance storm,'' one that put all emergency response organizations on a stand-by alert but that did not require a great deal of effort to handle. Such incidents were not considered unusual either by residents or emergency management officials. The areas that experienced flooding were areas that often had water-related problems whenever a heavy amount of rain fell. Because of these storms, the actual rainfall at Honolulu Airport for 1987 almost reached the annual average expected by December 31. On an annual calendar basis, the normal rainfall at Honolulu Airport is 23.47 inches, whereas during 1987 the actual rainfall was 22.88 inches. The normal rainfall for December is 3.43 inches, but during December 1987 the actual rainfall was 16.65 inches, which was five times greater than normal December rainfall and 73.8 percent of the 1987 total.
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 Figure 1 A map of the affected watersheds in southeastern Oahu.
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 The weather forecast carried by the Honolulu Star Bulletin on the evening of December 31 read: "Cloudy with showers, some heavy. Continued showery tonight." It appeared that the year 1987 would conclude on a wet note. THE NEW YEAR'S EVE STORM By 3:00 p.m. on Thursday, New Year's Eve, heavy rain began. Before closing the office that evening, a representative of the OCDA spoke with the NWS to determine whether any flood watches or warnings were anticipated (Kekuna, 1988). At 4:40 p.m., NWS reported that there were no data to indicate the need for any type of flood advisory, although heavy rains might occur during the night. On the basis of this information, the OCDA did not go to an alert status before the long holiday weekend began. In emergency situations the OCDA is responsible for mobilizing the city/county emergency operations center and coordinating emergency response efforts. Thus, it is the principal local-level emergency management agency on the island of Oahu, which covers over 200 square miles and has a population of approximately 800,000 people. When emergency weather alerts are issued, the OCDA is the primary local contact for the NWS. However, when OCDA offices are closed, as they were after 5:00 p.m. on Thursday, December 31, the Communications Center of the Honolulu Police Department (HPD) becomes the primary contact for the NWS. If the weather situation worsened during the evening and some type of weather advisory were to be issued, HPD would be contacted immediately. Because it was New Year's Eve, HPD's District 1 had double shifts of officers on patrol from Honolulu to Hawaii Kai. By 7:15 p.m. the HPD District I dispatcher was receiving a substantial number of calls from officers on patrol who were reporting flooded intersections, running water, debris, mud, and traffic control problems due to flooding. At 7:45 p.m. the dispatcher for HPD's District 4, covering the windward area of Oahu, which includes Kaneohe and Kailua, also began receiving calls that major highway flooding was occurring in the area. The NWS had still not issued a flood advisory, watch, or warning statement. At approximately 8:00 p.m., the HPD Communications Center contacted the NWS about the heavy rains, road closures, and household evacuations that were taking place in Waimanalo, Hawaii Kai, and Kuliouou. Because of this information and the fact that a raingauge in Waimanalo had recorded 4.7 inches of rainfall within the past 6 hours, the NWS issued a flash flood warning. The warning message read: A flash flood warning is in effect at 8 p.m. HST for the southeast portion of Oahu from Aina Haina through Kuliouou and Hawaii Kai around to Waimanalo. A flash flood warning means dangerous flood conditions are imminent or already occurring. Take necessary actions immediately.
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 Many portions of Oahu are having ample rainfall this evening. However, an excessive steady rainfall is occurring over southeast Oahu from Aina Haina to Waimanalo. Special care should be taken near streams, low points in roadways, and dangers of landslides. The NWS then contacted a representative of the OCDA to apprise him personally of the warning and sent the warning out to the agencies and organizations connected to the NWS system. By 8:30 p.m. the electronic media—television and radio—were carrying the warning message and began reporting on developing "trouble spots" in the southeastern area of the island. Officially, this was the first notification that any type of emergency situation could occur. Until the issuance of this warning message, no coordinated emergency response had begun, even though police and fire department personnel were already responding to citizen requests for assistance with flooding problems. Also, citizens had not received any official notices that flooding was possible until it was already occurring. Because of the New Year's Eve holiday, there was some difficulty in locating and contacting emergency response personnel to fully activate the OCDA city/county emergency operations center (EOC) in Honolulu. However, by 9:00 p.m. the EOC had begun to respond to incoming calls for assistance and authorized the opening of the first evacuation center at Kaiser High School in Hawaii Kai to accommodate people forced to leave flooded homes. Although no formal request had been made by the OCDA for the state Civil Defense agency (SCD), headquartered at Diamond Head, to activate its emergency operations center, SCD officials began monitoring emergency communication frequencies as soon as the flash flood warning was issued. At 7:00 a.m. New Year's Day, the SCD's EOC was made partially operational with selective staffing in order to assist the OCDA. Two conditions developed that made it difficult for emergency response officials to gather data to assess the extent of damage and to identify developing trouble spots. First, high winds in the area prevented the use of helicopters for visually assessing flood conditions. Wind gusts up to 50 mph had been registered that night. Even under good conditions, however, a nighttime assessment would have been difficult due to the continuing rain. Second, mudslides and running water had caused the closure of two major highways by 10:00 p.m. The Pali Highway, the major overland artery to the Windward and Waimanalo areas from Honolulu, was closed by 8:30 p.m.; Kalanianaole Highway, the major artery along the coast between Honolulu and Waimanalo, was closed by 10:00 p.m. by the Honolulu Police Department. The closure of these two transportation corridors resulted in difficulties and delays in getting personnel and equipment into flooded areas to evacuate people and to remove mud and rock debris. It also stranded people who had gone into the area earlier in the evening to attend New Year's Eve parties and gatherings. By late evening many could not return to their homes in nonflooded areas. These "New
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 Year's guests" added to the numbers of people who required shelter and provisions during the night of December 31–January 1. The immediate attention of the emergency response agencies was focused in two areas because of incoming reports of water, debris, and mud floods—the Hawaii Kai area (including Aina Haina, Hahaione Valley, Niu Valley, and Kuliouou) and Waimanalo. Due to flooding that had started by 9:00 p.m., Halemaumau Street in Niu Valley and Kahena Street in Hahaione Valley sustained substantial damage to private homes, lifelines, and roadways into the areas. Due to the blockage of drainage systems by debris and rocks, unanticipated water and mud diversions occurred, causing extensive damage to many residential neighborhoods in the Hawaii Kai area that had not previously experienced flooding owing to their upland locations. The diversion of floodwaters was so erosive that by the morning of January 1 Kahena Street had been transformed into a ravine 10 to 20 feet deep and about 30 feet wide in some spots. Boulders and mud rolled into homes, destroying or severely damaging them. Residents of Hahaione Valley were aware of the developing problems as early as 7:30 p.m. on New Year's Eve when neighbors attempted to divert some of the running water away from endangered homes in the area, an effort that was not successful. Waimanalo, a relatively low-lying area that often experienced some flooding during periods of heavy rain, received significant flooding during this event. The heaviest rainfall fell in Waimanalo, which received 10.5 inches within a 12-hour period. Homes were inundated, often with reports of 5 feet of water swirling through them. Electricity outages, which occurred throughout many of the flooded areas, were most severe in Waimanalo. An electrical substation serving the area was inundated with waist-deep water, causing a loss of power to 1,300 customers. Although power was generally restored to the area by 2:30 a.m., by rerouting power from other substations into the Waimanalo area, people were asked to conserve energy because of emergency demands on the reduced-capacity system. Throughout the night a variety of emergency response agencies were called upon to meet the demands of the flood situation. HPD officers provided traffic control, evacuation, and security services; firefighters responded to emergency medical requests and provided evacuation services; public works and transportation departments attempted to clear debris and mud from roadways; utility companies attempted to restore service to customers. The OCDA made a special request to the U.S. Marine Corps for use of its amphibious vehicles to evacuate residents from areas that police and firefighters were unable to reach. The Red Cross began opening evacuation shelters for people who had been displaced from their homes or who could no longer reach home. Although 13 locations were initially identified, only 7 shelters were actually opened that night. Eventually, almost 1,100 people were served by these shelters on New Year's Eve and New Year's Day (Table 1). Around midnight, a third area, which included Kailua and Kaneohe, experienced
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 TABLE 1 Number of Individuals Served by Mass Care Shelters Shelter Date Opened Date Closed Person Served Kailua Area Kailua Intermediate School 12/31/87 01/02/88 325 Kailua Elementary School 12/31/87 01/01/88 200 Trinity Presbyterian Church 12131/87 01/01/88 200 Kalaheo High School 12/31/87 01/01/88 50 Kailua Recreation Center 01/02/88 01/08/88 15 Hawaii Kai Area Kaiser High School 12/31/88 01/01/88 135 Aina Haina Elementary School 12131/87 01/01/88 120 Other areas Waialua High School 12/31/87 01/01/88 20 TOTAL 1,065 Source: Data provided by the Red Cross. major flooding. Due to the overtopping of a flood levee protecting the Coconut Grove area of Kailua from the Kawainui Marsh and the inability of flood canals draining the area to handle excessive runoff, many Kailua residents were awakened in the early hours of 1988 by flood waters rushing through their homes. A 6-square-block area in Kailua between the Kawainui drainage canal and Oneawa Street and the Kalaheo area of Kailua near the canal were completely inundated with 2 to 5 feet of water at the height of the flood. By 4:00 a.m., Marines had been called in to assist police and firefighters in evacuating people from the Coconut Grove area. About 275 people were eventually rescued from their flooded homes in a variety of vehicles, including city buses, troop carrier vehicles, and fire department trucks. These windward-side coastal residents had no warning that a flood was imminent. At this time the flash flood warning had extended only to Waimanalo, not farther up the windward coast to Kailua or Kaneohe. In the last hours of 1987, media attention and emergency response efforts were focused on the obvious flood situation in the Hawaii Kai area. Also, rain had been less heavy along this coastal area than it was on the watershed areas above, which perhaps gave residents the impression that they were not in danger. Ultimately, however, the number of residences damaged in the Kailua area was almost nine times that in the Hawaii Kai area (Table 2). Also, the number of homes sustaining major damage in Kailua (i.e., damage sufficiently extensive to make the home unlivable for some period of time) far exceeded that in Hawaii Kai. In terms of the social impact of this disaster, the older working-class neighborhoods in
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 TABLE 2 Red Cross Residential Damage Assessment by Location and Extent of Damage Extent of Damage Location Destroyed Major Minor Total Kailua Area Kailua 2 274 676 952 Waimanalo 2 23 53 78 Windward 0 0 73 73 Subtotal 4 297 668 1,103 Hawaii Kai Area Aina Haina 0 2 7 9 Hahaione Valley 1 3 28 32 Niu Valley 3 13 89 105 Kuliouou 0 0 8 8 Subtotal 4 18 132 154 TOTAL 8 315 934 1,257 Source: Data provided by the Red Cross, January 8, 1988. Kailua sustained much greater losses, both relatively and absolutely, than did the more affluent middle- to upper-middle-class neighborhoods in Hawaii Kai. Residents were startled by the events. The U.S. Army Corps of Engineers had designed and completed by 1966 a major flood control project in Kawainui Marsh that supposedly had alleviated flooding problems experienced in the 1920s and early 1950s (U.S. Army Corps of Engineers, 1956). However, development in the Hahaione, Kuliouou, and Niu valleys had slowly progressed deeper into the valleys, and the Upper Hahaione Valley was a relatively new development. Furthermore, the meteorological culprit of the flood events was a slow-moving frontal remnant that had stalled over Oahu on December 31, 1987. Surface north-northeasterly winds had lifted over the southern rampart of the Koolau range, producing huge precipitating clouds that were anchored by strong south-southwesterly winds aloft. These seemingly nonthreatening weather conditions, in conjunction with public expectations of safety, contributed to the surprise experienced by residents when flooding occurred. EMERGENCY MANAGEMENT AND HAZARD-MITIGATION CONCERNS It can be concluded that the emergency response to the Oahu disaster as it progressed was effective. That is, local resources were able to cope with the demands of coor
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The New Year's Eve Flood on Oahu, Hawaii December 31, 1987–January 1, 1988 dination, rescue, and sheltering as they occurred under very difficult circumstances. However, other questions concerning emergency response planning and flood mitigation have been raised. The first set of questions pertains to the flood warning system. Why was the NWS unable to issue either a flood advisory or a flood watch prior to the actual onset of flooding? Did a flood warning system exist that could have been used to warn residents, especially those on the windward side of Oahu, about the flood possibility? The meteorological conditions and other information that the NWS had during the preflood period resulted in the issuance of a warning only after the flooding began, indicating that the warning system was inadequate in this situation. As a result, no emergency response personnel were formally mobilized until after flooding was in progress. The second set of questions concerns the causes of the two different types of flooding experienced. One was the rapid onset of flooding in the Hawaii Kai areas of the island; the second was the flooding that developed slowly in Kailua due to overtopping of the Kawainui Marsh levee. Could these types of flooding have been mitigated? Were the mitigation efforts taken adequate? The two types of flooding events and an assessment of the adequacy of planning and mitigation efforts are discussed in Chapters 2, 3, and 4. The third question concerns the adequacy of flood plain management as a nonstructural mitigation measure. Since the city and county of Honolulu were participating in the National Flood Insurance Program, did the floodplain maps provide adequate guidance for the damage that resulted? This question is discussed in Chapter 5.
Representative terms from entire chapter: