City crews have brought in sandbags in anticipation of high surf conditions at Oahu beach parks, where water levels are expected to rise tonight and peak Friday — bolstered by astronomical “king tides.”

The Department of Parks and Recreation placed more than 500 sandbags along the makai side of Ala Moana Beach Park and over 200 sandbags at Kuhio Beach Park in Waikiki in preparation for the first onslaught of the highest water levels the state will experience this summer. Peak astronomical tides of the year, known as “king tides,” and the current summer swell are expected to push water levels to their highest Friday, and again around June 3 and July 21.

Mayor Kirk Caldwell said today at a press conference that the state can expect 8-foot surf to impact south shores. He said officials are unsure of how much impact the high surf will have.

University of Hawaii Sea Grant College agent, Matthew Gonser, said king tides are “very predictable and forecastable events.”

“The king tides provide us with an opportunity to somewhat look into the future.We have models and we have projections for sea level rise,” said Gonser. “But the actual visual experience is very powerful and really critical information to better calibrate those models and then incorporate that information into planning and other future decisions.”