The importance of heeding flash flood warnings was underscored by fire officials and hiking experts Tuesday morning when four teen-agers were swept away while trying to cross Kalihi Stream.
The teenagers were treated at a local hospital after being caught in the rising stream caused by a heavy downpour in Kalihi Valley in the area known as "Ice Ponds."
The National Weather Service had posted a flash flood warning for Oahu from 7:30 a.m. until 10 p.m. Tuesday, interspersed with flood advisories, but there should be a gradual clearing today.
"There may still be lingering showers over windward slopes till the morning, but the intensity of the rainfall should diminish rapidly," Vladimir Ryshko, forecaster for the National Weather Service, said Tuesday night.
Heavy rain fell through most of Tuesday over the Koolau Range and to a lesser degree over the Big Island’s windward and leeward areas. Thunderstorms moved in around 7 p.m., and some showers fell over the leeward area of Kauai, Ryshko said.
Capt. Terry Seelig, Honolulu Fire Department spokesman, said seven teenagers from Pearl City had gone to Naohia Falls to swim. He said the group was heading back at about 11 a.m. when four of them were caught in rising water as they crossed Kalihi Stream.
Emergency Medical Services said three girls — two of them 17 years old and the third 16 — and a 16-year-old boy were swept away.
"The water started rising," Seelig said, "and the four were caught, swept downstream until they managed to catch themselves on some rocks."
ALL four were taken in stable condition to the hospital. The four teenagers were treated for minor scrapes and bruises, authorities said.
"They were very, very fortunate, Seelig said.
Darrell Teruya, a hiking coordinator with Hawaiian Trail and Mountain Club, said: "With the flash flood warning, we tell our people not to venture any place because stream crossings can be dangerous, especially in Kalihi Valley because you’ve got water coming down from two sides of the valley.
"Actually, any stream crossing in the islands are hazards," Teruya said.
Ryshko said factors came together for Tuesday’s heavy rainfall.
"Moisture provides fuel for shower development, and cold air over warm air is unstable," he said.
Most of the heavy rain on Oahu fell in areas where the water could run off into the ocean, and water courses were free from debris, Ryshko said.
"In general, Oahu seemed to have dodged a bullet," he said.