State
Rising
Guernsey’s large tides make its coastline spectacular, but they can also create strong currents and rapidly cut off beaches, rocks and coastal routes. Here is how to read the tide, avoid the common hazards, and call for help in an emergency.
The island has one of the largest tidal ranges in the world, with the sea rising and falling by around 10 metres on the biggest tides. A beach, causeway or stretch of rocks that appears safe and open can be covered surprisingly quickly as the tide returns. Strong tidal streams, waves, slippery rocks and unstable cliffs can also create risks close to shore.
There are no lifeguards stationed on Guernsey’s beaches, so everyone entering the sea or exploring the coast needs to assess the conditions and take responsibility for their own safety.
Call 999 or 112. For anyone in the water, cut off by the tide, or in difficulty on the cliffs or shore, ask for the Coastguard. For other emergencies, ask for the service you need. Then give the operator:
Stay on the line and follow the operator’s instructions.
Do not enter the water to attempt a rescue unless you are specifically trained and equipped to do so. Call the Coastguard and, where possible, throw the person something that floats.
Guernsey’s tides do much more than make the beach wider or narrower. At low water, large areas of sand, reef and rock are exposed. As the tide rises, the water can return around rocks, headlands and sandbanks, cutting people off from the shore. The difference between low and high water can be around 10 metres on the largest tides, and the coastline changes roughly every six hours.
Do not plan merely to arrive before high tide. In some places the route back becomes unsafe or disappears several hours earlier.
Know when the tide turns, know where your exit is, and leave more time than you think you need.
On a broad beach the water may not move towards the land in a straight line. It can fill channels, flow behind rocks and surround raised areas, leaving someone apparently standing above the water but separated from the shore. Children exploring rock pools should stay close enough to be seen and reached quickly.
Spring tides occur around the new and full moon. They produce higher high waters, lower low waters and generally more water movement than neap tides. They are often the most interesting tides for rock pooling, but they also increase the risk of tidal cut-off, stronger currents, waves reaching farther up beaches and slipways, and exposed rocks becoming submerged quickly.
Even when the surface looks calm, water may be moving strongly beneath or across it. Guernsey lies among narrow channels, reefs, headlands and offshore islands, and large quantities of water move around these features with each tide. A sheltered-looking bay is not automatically safe. Currents may be strongest:
Signs of moving water can include floating seaweed or foam travelling sideways, an unusually smooth channel through breaking waves, rippled water beyond a headland, waves breaking differently over one section of beach, or swimmers and paddleboards drifting sideways.
If in doubt, stay out.
A rip current is a flow of water moving away from the shore. It can carry a swimmer into deeper water surprisingly quickly. Rips can change position and strength with the tide, swell and shape of the seabed, and can be difficult to identify even for experienced swimmers. Possible signs include a darker or calmer channel between breaking waves, foam moving away from shore, debris carried seaward, or waves breaking on either side but not in the middle.
Trying to fight directly against a rip can quickly cause exhaustion.
Guernsey does not have lifeguards stationed on its beaches, so check the weather and tides, know your limits and never swim alone.
An offshore wind blows from the land towards the sea. It can make the water near shore look flat and sheltered while pushing swimmers, inflatables and paddleboards away from land. Avoid taking inflatable toys or lightweight craft onto the sea in an offshore wind.
Sea temperature can stay low even on a warm day, and sudden immersion can cause cold-water shock. If you fall in unexpectedly, follow the RNLI’s Float to Live advice: resist the urge to thrash, lean back, extend your arms and legs, and float until your breathing settles before calling for help or swimming to safety.
Large waves can knock a person over, wash them from rocks or carry them into deeper water. A calm gap between waves may be followed by a much larger set. Never turn your back on breaking waves when standing on rocks, piers, sea walls or exposed slipways.
During storms, keep well back from sea walls and exposed coastal roads, avoid standing on wet rocks to watch the waves, do not cross barriers or ignore warning signs, and remember that one unusually large wave can reach much farther than those before it.
Some Guernsey bays can be reached only by steep paths, steps or rocky routes, and moving between bays along the shore may involve scrambling over loose or slippery rock that becomes impassable as the tide rises. A route that looks straightforward from the beach may hide steep drops, algae-covered rock, loose stones, deep gullies, or sections with no safe way back to the path.
Never climb an unfamiliar cliff face as an improvised escape from a rising tide. Loose ground and vegetation may give way, and rescuers may struggle to reach you.
Do not assume that adjoining beaches are safely connected at low water. For example, signs at Moulin Huet warn that walking or swimming between Moulin Huet and Petit Port can be dangerous, that parts of the beach can become cut off, and that people should keep away from the base of the cliffs.
Rock falls occur naturally around Guernsey’s coast, particularly after prolonged rain, frost, storms or winter weather. Do not sit directly beneath a cliff, let children dig into cliff banks, climb cliff faces, ignore falling-rock signs, or assume a previous rock fall has made an area safe.
Keep a sensible distance from the base of cliffs, especially where there is fresh rubble, exposed soil or recently fallen stone. Warning signs may apply to a very specific area, so read them on arrival and do not move or pass barriers.
Sea caves can flood rapidly and may contain strong currents, waves, loose rock and deep pools. Never enter a cave unless you know its tidal access window, the sea is calm, you have a reliable light, someone knows where you are, and you have suitable experience and equipment.
VisitGuernsey strongly advises using an experienced guide for the Bailiwick’s sea caves, because tides are changeable and local knowledge is needed. Do not enter a cave simply because it is accessible when you arrive; consider whether the entrance will still be open on your return.
Rock pooling is one of the best ways to explore the shore, but rocky areas become slippery and can be surrounded by the incoming tide.
Barnacles, limpets and broken shells can cause cuts, and seaweed-covered rocks can be extremely slippery even when they look dry.
Jumping into the sea from rocks, piers or harbour structures can cause serious or fatal injury. Water depth changes dramatically with the tide, and even where someone has jumped safely before there may be submerged rocks, insufficient depth, debris, strong currents, difficulty climbing out, or boats nearby. Guernsey Coastguard has warned that the Bailiwick’s bays and harbours can rise and fall by the height of a two-storey building, and that local currents can move faster than a person can swim.
Do not jump unless the location is formally managed for that activity and conditions have been assessed by a competent operator.
Stand-up paddleboards and kayaks can quickly be carried away by wind and tide. Before launching, check the wind and tidal stream, consider where a capsize would take you, wear an appropriate buoyancy aid, carry a waterproof means of calling for help, dress for the water temperature rather than the air, and tell someone your route and return time.
Use the correct type of leash for the environment: one that suits open water may be dangerous in moving or confined water where it could snag. Do not launch in an offshore wind unless you have the experience and equipment to manage it.
Inflatable toys are designed for pools, not open sea. Wind can carry them offshore far faster than someone can swim. Keep inflatables out of the sea when the wind is offshore, the water is rough, visibility is poor, or the tide is moving strongly. Never tether a child to an inflatable.
Rock anglers should be especially cautious on exposed headlands and lower ledges. Check the tide and swell forecast, observe the sea before moving onto a ledge, wear a lifejacket or flotation device, use suitable footwear, keep away from weed-covered edges, never fish alone in an exposed spot, carry a phone or locator on your person, and plan how you would leave if conditions worsen. Calm weather does not mean there is no swell; waves from distant weather systems can arrive unexpectedly.
Dogs can be swept away by waves or become trapped below cliffs. Keep dogs under close control near cliff edges, rough seas, tidal causeways, deep rock pools and unstable slopes.
If a dog is swept into the sea, do not enter the water after it. Call 999 or 112 and ask for the Coastguard. Dogs often reach the shore themselves, while owners attempting a rescue may become casualties.
What are the waves, wind and currents doing?
Is it rising or falling, and when could your route be covered?
Are you with someone, and does anybody know where you are?
Is it charged, protected from water and within reach?
For anyone in the water, cut off by the tide, or in trouble on the coast, ask for the Coastguard. Do not enter the water to rescue somebody: throw them something that floats, keep them in sight, and give the clearest location you can.
General guidance only, not a substitute for local knowledge or professional advice, and not for navigation. Tide predictions are astronomical and do not account for weather, wind or atmospheric pressure. Sources include the RNLI, Guernsey Coastguard and VisitGuernsey. Tides: ADMIRALTY® Tidal Data © Crown Copyright and database rights, reproduced with the permission of the UK Hydrographic Office. In a sea or coastal emergency call 999 or 112 and ask for the Coastguard.