High surf warning issued for Kauai and Niihau south shores

South-facing shores of Kauai and Niihau were under a High Surf Warning through 6 a.m. Tuesday, with the National Weather Service forecasting 10 to 15 feet of surf and warning that the danger could shift as conditions changed. Kauai County said the alert could be extended, dropped or modified, but for now the message was blunt: stay out of the water on exposed south-facing beaches and treat the shoreline itself as hazardous.

That warning carried real consequences for families heading to the beach, fishers working the coast and weekend visitors drawn to the South Shore. County officials said entering the water in the warned areas could cause serious injury or death, and even people who stayed on shore were at risk because large breaking waves can sweep across rocks and wet sand with little warning. The county also urged caution for shoreline walks and any ocean activity in the warning zone.

National Weather Service Honolulu described the system as a large long-period south-southwest swell coming from about 200 degrees. By Sunday morning, buoy 51002 south of the islands was already observing about a 4-foot swell at 19 seconds, with peak observations above 5 feet, a sign of powerful energy capable of producing dangerous surf on south-facing shores. Forecasters said surf along exposed south-facing shores was expected to hover around high surf warning levels through Monday, then get another reinforcement around Thursday that could keep conditions elevated for much of the week.

The weather service also noted that surf heights are measured as full-face surf from trough to crest, and that the advisory criteria for south- and east-facing shores changed on Aug. 2, 2021, from 8 feet to 10 feet. Coastal flooding during high tides was also possible through Tuesday, adding another layer of risk near the waterline.

Kauai County’s Ocean Safety Bureau said its work includes reducing drowning and water-related injuries, providing first aid and rescue services, and promoting beach and ocean safety awareness. The county told residents and visitors to check with a lifeguard at a guarded beach or call the Ocean Safety Bureau at 808-241-4984 for current conditions before heading out. For Kauai and Niihau, the safest course remained clear: keep off the south-facing surf until the swell drops and the warning is lifted.