(BIVN) – The National Weather Service in Honolulu has issued a High Surf Warning for all south-facing shores in Hawaiʻi, as a “historic south swell will produce dangerous waves” over the weekend.

The swell “will build all day Saturday and peak at High Surf Warning levels Saturday night through Sunday night,” forecasters reported, “then slowly decrease through the first half of next week.”

The swell direction will be out of the south at 170 to 190 degrees. Surf will build to 10 to 14 feet during the day Saturday, then rise to 12 to 16 feet – with occasional sets to 20 feet – Saturday night through Sunday night.

“Expect ocean water occasionally sweeping across portions of beaches, very strong breaking waves, and strong longshore and rip currents,” the National Weather Service warned. “Large breaking waves and strong currents may impact harbor entrances and channels causing challenging boat handling.”

Hawaiʻi County officials have already announced they will be closing beach parks along the south-facing shores of the Big Island this weekend. “The Beach Parks will be reassessed on Sunday, but with the swell continuing through Sunday and the possibility of debris in the parks, there is a chance they will remain closed until Monday,” a County news release stated.

Below is a list of the parks that will be affected by the closure:

Puna:

• Isaac Hale

Kaʻū:

• Punaluʻu (camping canceled for the weekend)
• Whittington/Honuʻapo (camping canceled for the weekend)

Kona:

• Miloliʻi
• Hoʻokena (camping canceled for the weekend)
• Manini Point/Napoʻopoʻo
• Honaunau Boat Ramp
• Kahaluʻu
• Magic Sands
• Pāhoehoe
• Honls
• Hāle Hālawai
• Old Airport

UPDATE – (7 p.m.) – The Hawaiʻi Department of Land and Natural Resources also reported multiple state beach parks will be closed, as well. The DLNR stated:

This large south swell is expected to be the largest seen in Hawaii over the last decade. Waves are forecast to peak in the 15-20 foot range on the south shores of each island, building all day Saturday to high surf warning levels Saturday night through Sunday night. Large wave run up and coastal impacts are expected, especially during the late afternoon high tides.

On Hawai’i Island, closures include:

• Hāpuna State Recreation Area
• Kua Bay
• Kekaha Kai

“We’re asking residents, particularly our surfers, boaters, and ocean gatherers, to exercise extreme caution along Southern shores this weekend,” said Mayor Mitch Roth. “The swells accompanied by the remnants of Hurricane Darby may cause unpredictable ocean conditions that could lead to serious harm. We don’t want to lose any of our loved ones and ask that folks don’t go out when in doubt.”