A northwest swell bringing potentially dangerous surf of up to 35-foot faces this weekend could also contribute to coastal flooding, officials said.

The National Weather Service and Oahu’s Department of Emergency Management are warning that minor coastal flooding could occur Sunday morning when the peak of the swell coincides with a 2.2-foot high tide.

Flooding may occur on low-lying property and coastal roads.

Ocean Safety Operations Chief Jim Howe said, "Visitors don’t realize just walking on the sand, the waves will sweep you into the surf."

Lifeguards on Oahu’s North Shore issued 861 preventive warnings Friday and performed four rescues and four assists.

A high-surf warning was scheduled to go into effect at noon today to 6 p.m. Monday for north- and west-facing shores of Niihau, Kauai and Oahu and the north shores of Molokai and Maui.

The surf will peak Sunday day with 25- to 35-foot waves on north shores and 20 to 25 feet on west shores before subsiding Monday.