011. Danger of Being Swept by Waves
Waves arise in a “wave‑amplification zone” where water meets the rocks and the height spikes sharply. This zone becomes especially hazardous when the depth is 1–2 m and wave height exceeds 1.5 m.
When a wave strikes the rocks, a reflected wave spreads backward, forcefully pushing the angler away. The energy of the reflected wave is proportional to the square of wave height and wavelength, so a 2 m wave with a 10 m wavelength exerts roughly four times the force.
Prevention: check the Korea Meteorological Administration marine forecast for any wave‑amplification zones before heading out, and only approach when wave height is 1 m or less. In a sudden situation, drop your body into the water immediately and brace yourself against the rock to maintain balance.
- Underestimating wave height Entering the water can cause a sudden shock and a fall
- If you are pushed backward without touching the rock, you can be swept and injured
022. Slip‑Induced Falls on Wet Rocks
Rocky shores become slippery as the tide rises, leaving fine shells and seaweed on the surface. The average coefficient of friction drops from 0.6 when dry to below 0.2 when wet.
When currents exceed 1–2 knot (0.5–1 m/s), the risk of slipping and falling backward increases more than threefold. If your center of gravity is ahead of the rock edge, you may rotate and fall into the water.
The recommended response is to wear shoes with rubber soles or spikes and to keep a triangular stance by holding the rock with your hands. Also, consult the tide table and avoid times when the tide changes rapidly.
033. Hazard of Being Caught in Rapid Currents
Around rocky shores, currents and wind can quickly form rapid flows; a current averaging 0.8–1.2 m/s can submerge a person to a depth of 1.5 m within 30 seconds.
Rapid currents relate directly to water mass flow (kg·m/s); at a flow speed of 1 m/s, a 1‑inch (2.54 cm) thick water jet exerts a force of 100 kg·m/s. This force wraps around the body and pulls, so an immediate anchor point is essential.
Prevention: before heading out, review the Korea Coast Guard “Marine Safety Map” for marked rapid‑current zones, and minimize approach based on wind direction (southeast or northwest winds) and current strength.
044. Injuries and Infections from Rock Fragments
When waves hit rocks, tiny fragments become suspended in the water. These fragments average 0.5–2 mm in diameter and are sharp enough to pierce skin, raising bacterial infection risk by 15 % within 24 hours.
Marine bacteria (e.g., seawater bacteria) can cause inflammation if the wound stays in water for an extended period, and delayed treatment may lead to tissue damage within 48 hours.
The response is to trim fingernails and toenails, keep a waterproof band and antiseptic ready, disinfect any wound immediately, and protect it with a pressure bandage. If you stay in water for a long time, rinse thoroughly and dry the area to prevent infection.