UPDATE: Persistent Downpours

Sunday, Aug. 26, 2018, 1:21 p.m.: Tropical Storm Miriam Forms

Persistent downpours may further aggravate the major flooding across Hawai‘i even as Lane departs.

While Lane will continue to track away from Hawaii early this week, needed sunshine and dry weather may not follow for the extensive cleanup and recovery efforts.

Tropical moisture will instead remain and fuel continued localized downpours.

Any substantial rain can worsen ongoing flooding and trigger new mudslides, further threatening lives and property. There may be new evacuation orders, or residents forced from their homes may not be able to return as quickly as anticipated.

More roads and bridges can be damaged, cutting off some areas from receiving aid.

“The most numerous downpours that follow Lane are expected to be over the typical windward locations on the Big Island and Maui County,” according to AccuWeather Senior Meteorologist Brett Anderson.

The east- and northeast-facing slopes of the Big Island were hit the hardest by Lane’s extreme rainfall. Feets of rain led to catastrophic flooding.

Localized downpours will also target the western islands of O‘ahu and Kaua‘i, mainly in windward areas, early this week. Isolated flash flooding can occur where Lane left the ground oversaturated.

Even in the absence of new flooding, the downpours can slow clean-up operations and the progression of flood waters receding.

“It will also be more humid by Hawai‘i standards across the islands early this week, which will put a strain on crews,” according to Anderson.

More typical trade wind weather is expected to return for the second half of the week.

Drier air will drop humidity levels to more typical Hawai‘i standards and cause showers to become very spotty in nature. The showers will continue to focus mostly on windward communities, and rainfall will be much less than what is expected from the downpours earlier in the week.

There is a risk for additional sporadic tree damage to occur as peak gusts could be strong enough to topple trees weakened by Lane and sitting in saturated soil.

In the wake of Lane, Tropical Storm Miriam has formed in the eastern Pacific Ocean. Miriam is expected to track westward and strengthen into a hurricane early this week. An eventual turn to the north is anticipated well before the storm nears Hawai‘i.

Residents of Hawai‘i need to remain vigilant for additional threats from tropical storms and hurricanes through autumn, due to a developing El Niño.

Sunday, Aug. 26, 2018, 9:30 a.m.: Flash Flood Watch Still in Effect for Big Island 

The National Weather Service reports that a Flash Flood Watch remains in effect for Hawai‘i Island.

Rain will continue through early next week, so  be careful when traveling on the roads. Closures may occur without any notice.

Additional information:

The United States Postal Service reports that all post offices except Pepe‘ekeo Post Office will deliver mail today. However, there are no retail services or mail pickup from blue USPS mail boxes.

State Highways reports a one lane closure on Highway 19 at mile marker 28-29 (Ka‘awalii Gulch). This closure is to allow crews to remove a dangerous boulder from the hillside.

State Highways has installed a temporary traffic light on Highway 11 near mile marker 30 (Volcano Golf Course) due to a one lane closure. This closure will allow crews to make repairs to earthquake and flood damaged sections of the highway. Repairs are expected to last about two weeks.

All county parks remain closed until further notice.

The Hawai‘i State Department of Health is advising the public to stay out of streams, coastal and standing waters that are contaminated by storm water. Storm water may contain harmful micro-organisms from overflowing cesspools or septic tanks as well as animal waste washed into streams and storm drains.

To report flood damage to your property, call (808) 643-5555.

The current map of road closures can be found here.