Why are rip currents hazardous?
Rip currents and longshore currents are hazardous because of their ability to physically move water-users from a relatively safe region where they are in control, to a region of greater hazard. Typically this will be deeper water further from the shore or a region of heavy breaking waves, but it could also be towards a collision hazard like a headland, rocks or a coastal structure.
Video: RNLI rescue where a current has taken an inexperienced surfer towards a rocky headland
While it is clear that rip current present a hazard to water-users, it is the ability of a water-user to safely respond to the movement of a rip current that will affect their risk of injury or drowning.
How does human behaviour affect rip current risk?
Ability
It is important to consider the ability of the water-user to deal with the prevailing rip current hazard. For example, the risk of harm to the water-user in a rip current will be very different for an experienced surfer who is strong swimmer and has a floatation aid (surfboard), when compared to a inexperienced bather of average pool swimming ability on their first visit to the beach.
Ability to deal with rip movement will depend upon:
Swimming ability & floatation
- The ability of a swimmer to get out of a rip current safely will depend on their swimming ability. Both swimming speed and fatigue rate are important factors with fatigue rate being controlled by fitness and experience. Fatigue rate and the ability to keep head above water are dramatically increased when the water-user has floatation (e.g. bodyboard).
- Safe exit from a rip will either require a passive or proactive strategy. A passive strategy requires the water-user to either float or tread water and wait for a rescue or for the rip to return them the beach (in the case of a recirculating rip current). A proactive strategy requires swimming/paddling out of the rip current to a region of safety (e.g., across the rip flow to a shallower sandbar).
- Turbulent waters and breaking waves make swimming challenging. Therefore, it is important to consider swimming ability in the context of surf experience. Confidence in ability without practical experience in the surf can create high-risk situations.
Experience
- An experienced water-user (e.g., seasoned surfer/sea swimmer) will understand how a rip current is likely to behave, understand their own limitations and recognize the water movements in the surf zone. This experience will dramatically affect the response of a water-user to the rip current, enabling informed decision making, reducing panic and saving energy.
Response
The risk of harm will increase with decreasing experience and understanding. An inexperienced bather may experience:
Disorientation & panic
- Rip currents can create panic and cause an inexperienced bather to behave irrationally. Rip flows can move people quickly before they have a chance to notice and react accordingly. Rip pulsing and changes in circulation pattern can enhance this effect.
The surf zone is a foreign environment to an inexperienced bather with little experience or understanding of waves and currents. This can lead to panic and poor decision-making when in a rip current.
This video shows an RNLI rescue, illustrating how an inexperienced bather can panic and get into real difficulty, even though it appears that the bather is still within their depth.
Exposure
When assessing the risk that rip currents pose to bathers it is also important to consider their potential exposure to rip currents.
Rip exposure is the likelihood that a typical bather would be able to interact with the surf and rip currents. Under large waves, most inexperienced bathers are kept to the water’s edge due to the force of the waves. Research conducted by Plymouth University and the RNLI has shown that rip current conditions with the greatest impact often occur under small/medium swell waves, when rip currents are still relatively strong and large numbers of water users are able to interact with the surf and are therefore more exposed to rip current hazards.
