The deaths of two adults who were swept into the sea by powerful waves at a North Shore beach on Monday, followed Wednesday by the separation of a teenage kayaker from his paddling team off Waikiki, pose stark reminders that the ocean holds mighty, unpredictable and potentially life-threatening power.

At this time of year, rough seas, high waves, dangerous currents and other treacherous conditions can be commonly encountered on any side of the island. Preparation and a healthy embrace of caution are key to staying safe.

The adults who were swept to their deaths were on the sand at Ke Iki Beach, just north of Shark’s Cove, a popular summer snorkeling location when waters are typically calm. In mid-October, however, waves begin to rise, and extremely high surf is common. Swimmers at any level are advised to stay out of the water, but here, those swept away weren’t trying to swim; instead, they were in the wrong place at the wrong time.

Though lifeguards patrol, there is no dedicated station at Ke Iki Beach; in fact, there is no obvious location for one, because winter waves come up so high. Other beaches around the island have no towers, and it’s not practical to have them everywhere — so the difference between survival and tragedy can come down to avoiding beach dangers.

The teen who was initially lost at sea about 6:30 p.m. Wednesday was, very thankfully, found alive at daybreak after a tense overnight search. He had gone adrift as the team approached Diamond Head from the north; encountering rough water, the others turned around, but the youth, in a slim, 20-foot-long kayak, went missing about a half-mile south of the Sheraton Waikiki Beach Resort.

Rescuers searched by air from Diamond Head to Nanakuli — with no success until about 4 a.m. Thursday. Then, Coast Guard rescuers in a C-130 aircraft spotted the teen in the ocean near the Waikiki Natatorium, clinging to the kayak. An off-duty lifeguard who was already in the water brought the kayaker to Ala Wai Boat Harbor, suffering from exhaustion, dehydration, exertion and cold exposure.

For the casual swimmer or surfer, a first lesson here is “If in doubt, don’t go out — or even get too close.” If many others are not gathered on a stretch of beach or in the water, there may be a good reason for that; don’t “explore” if unaware of risks.

It’s also advisable to use the buddy system when in the water — to keep tabs on one’s fellow paddlers or swimmers, so that if something happens, help can be called for immediately.

Many advocate that recreational boaters wear or at least keep a flotation device handy, and this is advice that’s ignored at one’s risk.

All who have even a passing interest in Hawaii’s nearshore waters and beaches owe it to themselves to learn about beach conditions and safety. Information is readily available — but it doesn’t typically come to the beachgoer; it must be sought out.

One essential source: HIOceanSafety.com, a website maintained by Hawaii’s Department of Health in cooperation with the state’s Drowning & Aquatic Injury Prevention Advisory Committee, which coordinates education and advocacy. Representatives from various islands’ lifeguard associations and Honolulu’s Ocean Safety Division, fire departments and more state and private agencies are included.

The focus and information available at HIOceanSafety.com is invaluable, and can save lives. But the challenge in reaching those unaware of its existence or without digital access remains. Advisory committee member organizations must also address this need. After all, in addition to local residents, Hawaii hosts millions of tourists annually as well as military members who are wholly unfamiliar with the ocean’s dangers.

The “reach” in outreach and efficacy of Honolulu’s ocean safety messaging must be a top priority — especially by the new Ocean Safety Department, now that it has become a full-fledged department in city government.