High-surf warning extended for south shores; brown water advisory for parts of Oahu

The high-surf warning from a South Pacific swell has been extended through 6 a.m. Tuesday for the south shores of all Hawaiian islands.

The National Weather Service in Honolulu reports that “a historic south swell” will create dangerous, breaking waves occasionally sweeping across portions of beaches.

The south shore surf, which peaked at over 20 feet over the weekend, was falling but still expected to reach 12 to 16 feet.

According to forecasters, large breaking waves and strong currents may affect harbor entrances and channels which may cause challenges for boaters. Exercise caution when entering or leaving ports of south-facing harbors due to potential water surges over the next couple of days.

Meanwhile, a brown-water advisory has also been issued for the east-, south- and west-shores of Oahu after high surf and heavy rain resulted in stormwater runoff entering coastal waters.

“The public is advised to stay out of flood waters and storm water runoff due to possible overflowing cesspools, sewer, manholes, pesticides, animal fecal matter, dead animals, pathogens, chemicals, and associated flood debris,” according to a statement from the state Department of Health’s Clean Water Branch System. “Not all coastal areas may be impacted by runoff, however, if the water is brown stay out. Continue to practice good personal hygiene and follow-up with your primary care physician if you have any health concerns.”

In addition, a small craft advisory is in effect until 6 p.m. today for all coastal waters. Conditions will be hazardous to small craft. The National Weather Service advises inexperienced mariners and those operating small vessels to avoid navigating in these conditions.

“Boaters should be aware of an increased number of surfers and bodyboarders utilizing the harbor channel to access surfing areas,” forecasters said.

Beaches that typically remain dry may be flooded and vulnerable low-lying coastal roadways may be overwashed.

“A combination of large surf and regular predicted water levels will lead to flooding of beaches that typically remain dry,” forecasters said.

Large, breaking surf, significant shore break, and dangerous currents make for hazardous conditions. Forecasters warn the public that anyone entering the water could face significant injury or death.