Hawaii braces for second Kona low in less than a week

HONOLULU (CN) — Hawaii was still assessing the damage from a storm last week when another arrived late Thursday, renewing fears of catastrophic flooding across islands where the ground has nowhere left to absorb rain.

At 5:35 a.m. on Friday, Honolulu issued an evacuation order for the Waialua and Haleiwa areas on Oahu’s North Shore, citing extremely dangerous flooding.

Officials ordered evacuations in Waialua due to rapidly rising water at the Wahiawa Dam. The reservoir reached 84 feet at the spillway, well above the 80-foot threshold that triggers warnings for the area downstream. 

The dam had already been pushed to the brink during last week’s Kona low. The U.S. Army Corps of Engineers has labeled the Wahiawa Dam a high-hazard dam, warning that its catastrophic failure would put 2,500 lives in danger.

Stephen Parker, a meteorologist with the National Weather Service in Honolulu, said the second storm’s danger is rooted not in its intensity but in what came before it.

“Because the ground is so saturated already, there’s no room left to absorb any more rain,” Parker said. “So pretty much all the rain that falls is turning into runoff, which has to then get to the streams and filled up the reservoirs very quickly.”

The result, he said, is a storm that looks less severe on paper but hits harder on the ground. On Oahu’s North Shore, gauges recorded 11 inches of rain overnight, comparable to the worst stretches of last week’s event.

“The rainfall rates, depending on where you are, have been pretty much what happened last weekend,” Parker said. “But it’s the fact that the ground is already saturated, it just can’t take anymore, that we’re seeing more rapid responses in flooding than we had last time.”

The new system lacks the pressure gradient that gave last week’s storm its destructive winds, which topped 78 mph near Schofield Barracks and exceeded 100 mph on Big Island summits.

That distinction offers some relief: Fewer downed trees means fewer power outages. More than 130,000 customers lost electricity during the first storm, and roughly 240 in East Maui still have no power as crews work to repair approximately 20 damaged utility poles.

Parker said the storm will continue to deliver intense rainfall through Saturday before shifting its heaviest bands east toward Maui and the Big Island, with conditions improving by Sunday night and a significant clearing expected by Monday.

But before residents can exhale, he added, there is the unsettling possibility of a third Kona low.

“It’s not especially rare,” Parker said, “We’ve got a rather stable pattern across the Northern Pacific now, and that’s allowing these Kona lows to set up kind of one after another.”

The first storm’s toll is still being tallied. The state Department of Transportation is projecting more than $23 million in highway damage statewide.

On Oahu’s North Shore, additional shelters have opened at Waialua High and Intermediate School. Other shelters include Leilehua High School, Mililani District Park, Kahuku Elementary School, Wahiawā District Park and Nānākuli High and Intermediate School.

Governor Josh Green said the Hawaii National Guard has been active since early this morning. In a message posted to his Facebook, he advised residents to listen to local authorities, stay off the roads and take evacuation messages seriously.

“This is Kona Two, which is the second phase of the storm," he said. “Though there may be less rain, that could mean increased flooding. Also, the dam, which has been safe, was getting close to 85 feet. That’s why we sounded the alarms and made sure people could get out of harm’s way.”

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