Flood in Hawaii, December 2, 1999

To put the events of 1 and 2 December into perspective, an upper-air low over the state destabilized the atmosphere, causing heavy rainfall, hail, snow, and periods of lightning. The most significant problem to occur on Oahu was the overflowing of the Lake Wilson dam near Wahiawa in the early morning hours of 2 December. This sent a torrent into Kaukonahua Stream, which rose past its banks and sent as much as four feet of water into yards downstream. Twenty homes were affected by the flood, with fifty residents having to be evacuated for a time from the Otake Camp section of Waialua.Torrential rains caused Waiawa Stream in lower Pearl City to overflow, and fire crews used a raft to reach five stranded residents in a three-story apartment building off Lehua Avenue in the early hours of 2 December.The upper low also dropped small hail on the upper slopes of Haleakala in Maui in the morning hours of 2 December. Icy conditions on the main road to the summit caused park officials to close it near the 7000-foot level from 4:40 AM to 8:00 AM.The storm left unusually deep snow on Mauna Kea on the island of Hawaii on 2 December, extending to as low as Hale Pohaku at the 9600-foot elevation. Drifts were as deep as two feet along the road to the 13,796-foot summit.In summary, several parts of Oahu and the island of Hawaii had 24-hour rainfall totals of more than five inches, and an upper Nuuanu site on Oahu exceeded seven inches for the 24-hour period ending 8 AM on 2 December. Heavy rain in Kauai's central mountains raised the level of the Hanalei River, but it did not get to flood stage. Ponding of roads, minor rock- and landslides, and isolated power outages were common for the early days of December in Kauai, Oahu, Maui, and the island of Hawaii.