HONOLULU (KHON2) — As of Sunday evening, Hawaii County continues to see heavy rain along southeast slopes and rainfall is expected to continue into Monday, Dec. 6.

For Maui County, the National Weather Service (NWS) said more widespread heavy rain is expected Sunday evening over Maui island — particularly the south slopes of Haleakala. The rain is then expected to move over to Lanai and Molokai after midnight.

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The NWS said a catastrophic rain event is possible and widespread of 10 to 15 inches of rain is expected, with isolated areas seeing 20 to 25 inches of rain.

For Kauai, narrow bands of heavy rain may develop Sunday evening — similar to what Oahu saw Sunday morning — with a lull in activity overnight.

The slow-moving system can easily trigger flooding, landslides, road closures and property damage.

“Anytime we’re looking at those types of rain totals, there’s the possibility of getting catastrophic impacts,” said Christopher Brenchley, NWS Honolulu Meteorologist in Charge. “It’s more than what you’d get with our typical flash flooding events, so we definitely want people to be aware of that.”

Brenchley also said Kona lows can bring other impacts like high surf, strong winds and snow to the summits. Astronomical high tides and high surf pushed sand and debris onto Kamehameha Highway Sunday morning, near Kualoa Ranch and Oahu’s North Shore.

On Maui, a section of Lower Honoapiilani Road in Napili was already flooding before noon Sunday. Piilani Highway near Kaupo remains closed after flooding on Saturday, Dec. 4, washed out the road.

On Sunday evening, Hawaii County Mayor Mitch Roth signed a Severe Weather Condition First Emergency Proclamation, declaring a state of emergency for the County of Hawaii. The county said the State of Emergency is due to the threat of imminent disaster on Hawaii Island by way of potentially heavy rainfall, lightning, high winds associated with thunderstorms and catastrophic flooding.

This emergency proclamation shall go into effect Sunday, Dec. 5, and terminate on Dec. 31 — unless terminated earlier or extended by a separate proclamation, or whichever will occur first.

The County of Maui said residents should anticipate a round of excessive rains late Sunday evening due to the “Kona Low” weather system. 

“As this unstable system continues to deliver large amounts of rain to Maui County, please prepare your household before flooding begins. If you are in a flood-prone area, take all necessary precautions to ensure the safety of you and your family.”

Maui Mayor Michael Victorino

“The Emergency Operations Center has been activated with partners from the Maui Police Department, Maui Fire Department, American Red Cross, and the Department of Housing and Human Concerns, among others,” said Herman Andaya, administrator of the Maui Emergency Management Agency (MEMA). “We are planning for potential needs that may arise from this ‘Kona Low.”

MEMA is working with social service agencies to notify the homeless population of the potential threat of flash flooding, especially in flood-prone areas. MEMA, in conjunction with the American Red Cross, is prepared to open shelters should evacuations become necessary.

On Saturday, Dec. 4, a portion of the Piilani Hwy near Pahihi Gulch was washed out and the road is still impassable. County Public Works crews were on scene to assess the road damage and repairs should begin in the upcoming week. The public is urged to avoid the area.

The Department of Parks and Recreation has closed Baldwin Beach Park on Maui due to flooding. Haleakala National Park is also closed due to high winds and winter weather. MEMA is in regular communication with dam/reservoir owners to alert them to monitor the water levels of their respective reservoirs and take needed safety precautions.

Due to significant expected rainfall through Tuesday, Dec. 7, the Department of Environmental Management advises all residents connected to the County’s wastewater (sewer) system to minimize toilet flushing, bathing, as well as using washers and dishwashers — Sunday through Wednesday morning.

The City and County of Honolulu said there is potential for Oahu to experience a catastrophic rain event during this period with intense rain bands.

Deep tropical moisture could produce widespread 10 to 15 inches of rain with isolated areas of 20 to 25 inches with numerous road closures and property damage possible with numerous road closures and property damage possible.

In addition, strong southerly winds 20 to 35 mph with localized gusts to 50 mph are possible Sunday night through Monday.

Additionally, officials said Maui County public schools will be closed to students and staff Monday. The situation will be evaluated again Monday to determine whether schools can resume safely moving forward.

Also on Maui, the Hawaii Department of Transportation (HDOT) confirmed power is out at the Kahului Airport terminal Sunday, Dec 5, and it happened around 5 p.m. According to a spokesperson from HDOT, the generator started but apparently did not work or failed. Maui Electric and American Electric are on the scene trying to restore power.

Kamehameha Schools will close its campuses on the Big Island and Maui until further notice.

Here is a list of emergency shelters open to the public on Oahu and Kihei:

  • Honolulu District — Kalakaua District Park, 720 McNeil St, Honolulu
  • Leeward District — Makaha Community Park, 84-730 Manuku St, Waianae
  • North Shore District — Sunset Beach Recreation Center, 59-540 Kamehameha Hwy, Haleiwa
  • Windward District — Kailua District Park, 21 S. Kainalu Dr, Kailua
  • Kihei Community Center  — 303 E. Lipoa Street, Kihei, 96753

According to officials, people are asked to bring their own food, bedding, water, toiletries and supplies. Pets are also allowed but must be kept in crates.

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“We are closely tracking the storm and coordinating with the various city, state and federal officials to help keep the public safe,” said Honolulu Mayor Rick Blangiardi. “Because this storm has potential for significant flooding, high winds and thunderstorms, we want people to be prepared and stay off the roads if possible during the storm conditions. We also urge people to stay informed and download the HNL Info app on their phone to receive important information and alerts.” 

“We urge all residents and businesses to be prepared and to exercise an abundance of caution during this time. Be prepared, pay attention to your surroundings and stay tuned to local news and official sources. Conditions could change quickly and it’s vital that you maintain situational awareness. We’ve had a tough year and we ask that everyone help each other out as much as possible” said Hiro Toiya, director of the Department of Emergency Management.