What Are Spring Tides?
Spring tides are the tides with the largest range between high and low water. They occur approximately twice a month, around the times of the new moon and the full moon, when the gravitational forces of the Sun and Moon combine to produce their maximum effect on Earth's oceans. Despite their name, spring tides have nothing to do with the season — the word "spring" refers to the water "springing" or surging higher than usual.
During spring tides, high tides are significantly higher and low tides are significantly lower than average. This means more of the coastline is submerged at high tide, and more of it is exposed at low tide. While this creates wonderful opportunities for exploration, beachcombing, and shellfish gathering, it also introduces real dangers that every coastal visitor should understand and respect.
Understanding the Risks
Spring tides are associated with several hazards that do not exist — or are much less severe — during neap tides. Awareness of these risks is the foundation of coastal safety.
Rapid Water Rise
The most dangerous aspect of spring tides is the speed at which the water level changes. Because the total tidal range is much larger during spring tides, the water must rise and fall more quickly to complete the cycle in the same time frame. On flat beaches and in shallow bays, the incoming tide can advance across the sand at walking speed or faster. People who venture far out onto exposed tidal flats at low tide can find themselves cut off from the shore in a matter of minutes as the tide turns.
This is particularly treacherous in areas where the beach is very flat and gently sloping, such as the bays of Normandy and Brittany in France, Morecambe Bay in England, or the Wadden Sea along the coasts of the Netherlands, Germany, and Denmark. In these locations, the tide can cover hundreds of metres of beach in a very short time.
Stronger Currents
Spring tides generate stronger tidal currents than neap tides. These powerful currents can be dangerous for swimmers, waders, and anyone in the water. In narrow channels, around headlands, and at harbour entrances, spring tide currents can reach speeds that even strong swimmers cannot overcome. Rip currents — already dangerous under normal conditions — become even more powerful during spring tides.
Estuaries and river mouths are particularly hazardous during spring tides because the large volume of tidal water flowing in and out creates fast-moving, turbulent currents. Some rivers experience a tidal bore — a wave that travels upstream as the spring tide pushes against the river's flow — which can be dramatic and dangerous to those caught unaware.
Coastal Flooding
The higher high tides of a spring tide can overtop sea walls, flood coastal roads and pathways, and inundate low-lying areas that remain dry during normal tides. When spring tides coincide with onshore winds and low atmospheric pressure, the resulting storm surge can amplify the flooding considerably. Some of history's worst coastal flooding events have occurred when severe storms coincided with spring tides.
Being Cut Off
Spring tides can cut off access to headlands, islands, causeways, and beach sections that are safely accessible during neap tides. The famous tidal causeway to Mont-Saint-Michel in France, Lindisfarne in England, or the Passage du Gois in France are classic examples of routes that become submerged during spring high tides. Every year, people are rescued — and tragically, some are lost — because they misjudged the timing or speed of a spring tide.
Safety Precautions for Specific Activities
Walking and Hiking
- Always check tide times and the tidal coefficient before walking on the coast. A coefficient above 90 indicates a large spring tide that demands extra caution.
- Know your route. Identify potential cut-off points and plan your walk so that you are moving away from rising water, not toward it. Have an escape route to higher ground.
- Time your walk appropriately. If walking on a beach or tidal flat, go out as the tide is falling and return well before it starts rising again. Never walk out on an ebbing spring tide if you do not have time to return before the flood.
- Watch for warning signs. Wet sand above the current waterline, fresh seaweed deposits, and water appearing in channels behind you are all signs that the tide is advancing faster than you realize.
- Carry a phone and know the emergency number. In case of emergency, call coastal rescue services immediately.
Swimming and Water Sports
- Swim at lifeguarded beaches. Lifeguards are trained to assess spring tide conditions and will adjust their safety zones accordingly.
- Be aware of currents. Spring tides produce stronger longshore currents and rip currents. If caught in a rip current, swim parallel to the shore rather than against the current.
- Avoid swimming near river mouths and harbour entrances during spring tides, where tidal currents are strongest.
- Wear a wetsuit or buoyancy aid in cold waters, as the shock of cold water combined with strong currents can be deadly.
- Never swim alone during spring tide conditions.
Fishing
- Choose your position carefully. Rock fishing during spring tides is particularly dangerous because waves reach higher on rocks and can sweep anglers off platforms that are safe during neap tides.
- Watch the waterline. If you are fishing from rocks or a beach, monitor the advancing tide and give yourself plenty of time to move to safety.
- Wear appropriate footwear with non-slip soles. Wet rocks are slippery, and spring tides wet areas that are normally dry.
- Carry safety equipment. A buoyancy aid, a whistle, and a phone in a waterproof case are essential when fishing during spring tides.
Shellfish Gathering
- Never go alone. Shellfish gathering at spring low tides takes you far from the normal shoreline. Always go in a group and stay in sight of each other.
- Set an alarm. It is easy to lose track of time when collecting shellfish. Set a phone alarm to remind you to begin returning to shore well before the tide turns.
- Know the terrain. Familiarize yourself with the area, especially any channels or depressions that will fill with water before the surrounding flats.
- Watch for incoming water channels. The tide does not always come in as a single advancing line. It can fill channels and depressions behind you, cutting off your return route before you realize it.
Boating and Kayaking
- Check current predictions. Spring tides create stronger currents in channels, straits, and around headlands. Plan your passage to work with the current, not against it.
- Be cautious near tidal races. Areas where spring tidal currents accelerate through narrow passages can create dangerous standing waves, whirlpools, and turbulence.
- Allow for greater depth variations. In harbours and anchorages, the greater tidal range means your boat will sit lower at low tide. Ensure adequate depth beneath the keel at all tidal states.
Special Precautions for Children and Families
Children are particularly vulnerable during spring tides because they may not understand the danger and cannot move as quickly as adults. Parents and guardians should:
- Keep children within arm's reach near the water's edge during spring tides
- Avoid letting children play on sand bars or offshore features that may be cut off by the rising tide
- Teach children about tides and the importance of watching the water level
- Ensure children wear brightly colored clothing so they are easy to spot
- Consider using a child's buoyancy aid even for beach play during spring tide conditions
What to Do If You Are Cut Off by the Tide
If you find yourself cut off by a rising spring tide, follow these steps:
- Do not try to wade through fast-moving water. Even ankle-deep water with a strong current can knock you off your feet.
- Call emergency services immediately. In France, call 196 (CROSS). In the UK, call 999 and ask for the Coastguard. In Spain, call 112. In Portugal, call 112. In Italy, call 1530 (Coast Guard).
- Move to the highest available ground and wait for rescue.
- Make yourself visible. Wave brightly colored clothing, use a whistle, or activate a phone flashlight.
- Stay calm. Rescue teams are experienced and will reach you. Panic leads to poor decisions.
Conclusion
Spring tides are a magnificent natural phenomenon that reveals parts of the coastline normally hidden beneath the waves. They offer unique opportunities for exploration, fishing, and shellfish gathering. But they also demand respect and preparation. By checking tide tables, understanding the tidal coefficient, knowing your local coast, and following basic safety precautions, you can enjoy the extraordinary spectacle of spring tides safely. The sea is always worthy of respect — never more so than during the powerful spring tides.