Apr 28, 2018

A Hawaiian island got about 50 inches of rain in 24 hours. Scientists warn it's a sign of the future

Hanalei, HI
USA
by
Heidi Chang
,
LA Times
Floodwaters on the Hawaiian island of Kauai turned orange, a sign of the high iron content in the volcanic soil. Photo: Brandon Verdura, Associated Press
Floodwaters on the Hawaiian island of Kauai turned orange, a sign of the high iron content in the volcanic soil. Photo: Brandon Verdura, Associated Press

Since the 1940s, the Hawaiian island of Kauai has endured two tsunamis and two hurricanes, but locals say they have never experienced anything like the thunderstorm that drenched the island this month.

"The rain gauge in Hanalei broke at 28 inches within 24 hours," said state Rep. Nadine Nakamura of the North Shore community. "In a neighboring valley, their rain gauge showed 44 inches within 24 hours. It's off the charts."

Actually, it was even worse. This week the National Weather Service said nearly 50 inches of rain fell in 24 hours.

Now, as Kauai continues to recover, scientists warn that this deluge on April 14 and 15 was something new — the first major storm in Hawaii linked to climate change.

"The flooding on Kauai is consistent with an extreme rainfall that comes with a warmer atmosphere," said Chip Fletcher, a leading expert on the impact of climate change on Pacific island communities.

He noted that the intense rainfall not only triggered landslides, it also caused the Hanalei River to flood and carve a new path through Hanalei.

...

"Just recognize that we're moving into a new climate, and our communities are scaled and built for a climate that no longer exists," said Fletcher, a professor of geology and geophysics at the University of Hawaii at Manoa.

Kawika Winter, a natural resource manager, put the storm in perspective.

"This is the most severe rain event [in Hawaii] that we know about since records started being kept in 1905," Winter said as he was about to catch a boat from Hanalei to join recovery efforts in Haena. "We're the most remote community on the North Shore, which is why being cut off is extremely devastating."

Winter is involved in research on climate change and community resilience — the ways places recover from unexpected and catastrophic events.

"In the Pacific Islands, we don't have the luxury of debating whether climate change is real," he said. "Climate change is affecting us, and has been for some time. There are striking similarities with the flooding that we experienced on Kauai and the recent flooding in California. The warmer atmosphere is holding more moisture and that builds up until it meets with cold dry air, creating this massive unstable system, which causes what some meteorologists are now referring to as a 'rain bomb.'"