Understanding Coastal Conditions for Coasteering: Tides and Swells - adventuro (2024)

Coasteering is a dynamic activity that involves traversing the intertidal zone of rocky coastlines through a combination of swimming, climbing, and jumping. For guides and enthusiasts, understanding coastal conditions, particularly tides and swells, is crucial to ensure safety and optimize the coasteering experience. This blog delves into the complexities of tides and swells, providing an academic insight into how these natural phenomena influence coasteering.

At adventuro, we alway recommend you go with a professional guide, for safety but also so you find the best routes and hidden beauties!

Understanding Tides

The Science of Tides

Tides are the periodic rise and fall of sea levels caused primarily by the gravitational interactions between the Earth, the moon, and the sun. This gravitational pull creates bulges in the ocean, leading to high tides in areas directly under the moon and on the opposite side of the Earth. As the Earth rotates, these bulges move, creating the tidal cycle.

Types of Tides

Spring Tides occur during the full moon and new moon phases when the Earth, moon, and sun are in alignment. This alignment amplifies the gravitational pull, resulting in higher high tides and lower low tides, thus creating the largest tidal range. During spring tides, the coastal terrain experiences significant changes. Routes that are accessible during low tide might become submerged during high tide, making planning and timing critical for safe coasteering.

Neap Tides, on the other hand, occur during the first and third quarter moon phases when the gravitational forces of the moon and the sun are perpendicular to each other. This results in less extreme high and low tides, leading to a smaller tidal range. Neap tides provide a more stable water level, making the coastal environment more predictable and often safer for beginners.

The UK predominantly experiences semidiurnal tides, with two high tides and two low tides each day of nearly equal height. Understanding the timing and height of these tides is essential for planning coasteering sessions, as certain areas may be accessible or safe only during specific tidal conditions.

Types Of Tidal Cycles

• Semidiurnal Tides: These involve two high tides and two low tides each day, which are nearly of equal height. This is common along most of the world’s coastlines, including the UK.
• Diurnal Tides: These involve one high tide and one low tide each day.
• Mixed Tides: These have two high and two low tides of varying heights each day.

Tidal patterns vary depending on geographic location and local environmental factors. The three primary types of tidal patterns are diurnal, semidiurnal, and mixed tides. Here’s an overview of where these tides occur:

Diurnal Tides

Diurnal tides feature one high tide and one low tide each day. This type of tide is less common globally but can be found in specific regions:

• Gulf of Mexico: Notably, locations such as Pensacola, Florida, and the coast of Texas experience diurnal tides.
• South China Sea: Parts of the South China Sea, including regions around the Gulf of Tonkin, exhibit diurnal tidal patterns.

Semidiurnal Tides

Semidiurnal tides, which have two high tides and two low tides of nearly equal height each day, are the most common tidal pattern and can be found in many parts of the world, including:

• Atlantic Coast of North America: From the East Coast of the United States up to the coast of Canada, semidiurnal tides are prevalent.
• European Coasts: The North Sea and the coasts of the UK and Ireland also experience semidiurnal tides.

Mixed Tides

Mixed tides display characteristics of both diurnal and semidiurnal tides, with two high tides and two low tides each day of different heights. These tides can be found in various parts of the world, particularly along coastlines that are influenced by both diurnal and semidiurnal forces:

• Pacific Coast of North America: The western coast of the United States, including areas like California and parts of Alaska, often experiences mixed tides.
• Indian Ocean: Certain regions, such as the northwest coast of Australia, exhibit mixed tidal patterns.

Understanding Tidal Patterns for Coasteering

Knowing the local tidal patterns is crucial for coasteering, as the type of tide influences the water levels and current strengths throughout the day. Here are some considerations:

• Diurnal Tides: With one high tide and one low tide each day, the tidal range can be significant, and planning must consider the prolonged periods between tidal changes.
• Semidiurnal Tides: The frequent tidal changes provide more opportunities for choosing the optimal time for coasteering, often during the slack tide periods (when the tide is changing and currents are weaker).
• Mixed Tides: These require careful planning to account for the unequal tidal heights and varying current strengths, ensuring safe navigation and timing.

Tidal Currents and Safety

Tidal currents, the horizontal movement of water associated with the rising and falling tides, play a significant role in the safety and feasibility of coasteering. These currents are strongest during the peak flow of incoming (flood tide) and outgoing (ebb tide) waters. The speed and direction of tidal currents can be influenced by the shape of the coastline, underwater topography, and local weather conditions.

Spring Tides generate stronger tidal currents due to the larger volume of water moving in and out. These powerful currents can pose significant risks, especially around headlands, narrow channels, and underwater obstacles. It is crucial to avoid coasteering during the peak flow periods of spring tides unless you are highly experienced and accompanied by a knowledgeable guide.

Neap Tides create weaker tidal currents, offering more manageable conditions for coasteering. The reduced water movement makes it easier to navigate and reduces the risk of being swept away by strong currents. However, even during neap tides, it is essential to remain vigilant and aware of local conditions.

Timing of Peak Tidal Flows

Peak tidal flows, or the maximum velocity of tidal currents, typically occur midway between high and low tides. This is when the water level changes most rapidly. Here’s how to calculate and predict these peak flows:

1. Understanding Tidal Phases:
   • Flood Tide: The period when the tide is rising (moving from low to high tide).
   • Ebb Tide: The period when the tide is falling (moving from high to low tide).
2. Timing Calculation:
   • Semidiurnal Tides: These tides have two high tides and two low tides within approximately 24 hours and 50 minutes. The time between successive high and low tides is about 6 hours and 12.5 minutes.
   • Peak Flow Timing: Peak tidal currents generally occur about 3 hours after the high tide and 3 hours after the low tide. This is because the tidal current speeds up as it moves towards mid-tide and slows down as it approaches high or low tide.

Example Calculation:

• If high tide is at 6:00 AM, the peak flood current will occur around 9:00 AM.
• If low tide is at 12:00 PM, the peak ebb current will occur around 3:00 PM.

Reading the Terrain with Regards to Tides

Understanding the intertidal zone, the area between the high tide and low tide marks, is vital for coasteering. This zone is where most of the activity takes place and is constantly reshaped by the tidal cycles.

During low tide, more of the coastal terrain is exposed, revealing rock pools, sea caves, and marine life. This provides excellent opportunities for exploration but also exposes slippery and sharp rocks, which require careful navigation. Low tide is often the best time for coasteering, as it allows access to otherwise submerged routes and features.

As the tide rises towards high tide, previously exposed areas become submerged, altering the landscape and potentially covering safe routes with water. High tide can make certain areas impassable and increase the risk of strong waves and currents. It is crucial to time your coasteering sessions to avoid being caught in rising tides that could trap you against cliffs or in narrow gullies.

Considerations for Heading Out with a Group

Before heading out, checking reliable tide and weather forecasts from sources like the UK Hydrographic Office or the Met Office is essential. These predictions help in planning the timing and route of the coasteering session, ensuring that you can avoid the most hazardous conditions.

When leading a group, safety is paramount. Conduct thorough safety briefings, emphasizing the importance of staying together and following the guide’s instructions. Ensure everyone has the proper safety gear, including wetsuits, helmets, and buoyancy aids. Implement a buddy system to enhance safety, especially in challenging conditions.

Route selection should be based on the group’s skill level and the current tidal conditions. Beginners should avoid routes with significant tidal changes or strong currents. Understanding the impact of tides on different parts of the route is crucial for avoiding dangerous situations. Identifying natural tide marks on rocks can help gauge the expected rise of the water and plan accordingly.

Monitoring Changing Conditions

Recognizing and responding to changing tidal and weather conditions is essential for safe coasteering. Here are key aspects to watch for and how to respond:

1. Tidal Predictions:
   • Use Tide Tables and Charts: Obtain local tide tables from reliable sources such as the UK Hydrographic Office or online platforms like Tide Times. These provide detailed information on high and low tides and their timings.
   • Mobile Apps: Apps like “Tides Near Me” or “Tide Alert (NOAA)” can provide real-time updates and alerts on tidal conditions.
2. Weather Conditions:
   • Check Weather Forecasts: Before heading out, check the latest weather forecasts from sources like the Met Office. Pay attention to wind speeds and directions, as these can significantly affect wave conditions and tidal flows.
   • Observe the Sky: Keep an eye on the weather while coasteering. Sudden changes in cloud cover, wind direction, or temperature can indicate approaching weather changes.
3. Visual and Environmental Cues:
   • Water Movement: Rapid changes in water levels, especially during spring tides, can create strong currents and waves. Observe how quickly the water is rising or falling and adjust your route accordingly.
   • Wave Patterns: Consistent wave patterns can indicate stable conditions, while erratic or increasingly powerful waves may suggest changing conditions.
   • Wind: An increase in wind speed can lead to rougher seas. Pay attention to wind direction, as onshore winds can push waves towards the shore, increasing their size and impact.
4. Safety Measures:
   • Set Timings: Plan your coasteering sessions to avoid peak tidal flows when currents are strongest. Aim to start your session shortly after high or low tide to take advantage of slower water movements.
   • Exit Points: Always identify and communicate safe exit points along your route. These should be accessible regardless of tidal changes.
   • Group Awareness: Keep the group together and maintain regular headcounts. Ensure that everyone understands the plan and is aware of potential hazards.
5. Real-time Adjustments:
   • Monitor Conditions: Continuously monitor tidal and weather conditions during your session. Be prepared to change the route or end the session early if conditions become unsafe.
   • Emergency Plan: Have an emergency plan in place, including signaling devices, first aid kits, and contact information for local emergency services.

Tides and tidal currents influence every aspect of the activity, from route accessibility to the strength of currents encountered. By mastering the knowledge of tidal patterns, currents, and reading the coastal terrain, guides can ensure a thrilling and safe coasteering experience for all participants. Always remember to check forecasts and prioritize safety in all coasteering adventures.

Tidal Predictions

Accurate tidal predictions are essential for planning coasteering sessions. Guides should consult tide tables and charts, which are available from various sources including local harbor authorities and online platforms such as the UK Hydrographic Office (UKHO).

Understanding Swells

Swells are long-wavelength surface waves generated by distant weather systems. Unlike local wind waves, swells can travel across vast ocean distances, impacting coastal conditions even when the local weather is calm.

Formation of Swells

Swells are formed by the transfer of energy from the wind to the water surface, typically occurring in areas of strong and persistent winds. The size and strength of swells depend on three main factors:

1. Wind Speed: Higher wind speeds generate larger swells.
2. Fetch: The distance over which the wind blows uninterrupted across the water surface.
3. Duration: The length of time the wind blows over the water.

Swell Characteristics

1. Wave Height: The vertical distance between the crest of the wave and the trough.
2. Wave Period: The time interval between successive wave crests passing a fixed point.
3. Wave Direction: The direction from which the swell is coming.

How Swell Affects Different Rock Formations in Coasteering

Swells, long-wavelength surface waves generated by distant weather systems, significantly impact the coastal environment, particularly the various rock formations encountered during coasteering. Understanding how swells interact with different rock formations is crucial for ensuring safety and optimizing the coasteering experience. Here’s a detailed look at how swells affect different rock formations:

Types of Rock Formations and Their Interactions with Swells

1. Cliffs and Steep Rock Faces
   • Impact of Swells: Swells hitting cliffs and steep rock faces often create powerful, reflective waves that can increase the intensity of the water’s impact. This can lead to hazardous conditions, especially during high-energy swell events.
   • Considerations for Coasteering: Guides should avoid areas with vertical cliffs during large swells due to the risk of strong wave rebound and the potential for being slammed against the rock face.
2. Rocky Outcrops and Headlands
   • Impact of Swells: These formations protrude into the ocean, breaking the incoming swells and creating areas of high turbulence. The waves often wrap around the headlands, creating strong lateral currents and eddies.
   • Considerations for Coasteering: Navigating around rocky outcrops requires careful timing to avoid peak wave impact. Coasteerers should be aware of the increased risk of being swept sideways by lateral currents.
3. Sea Caves and Arches
   • Impact of Swells: Swells can funnel into sea caves and arches, amplifying wave energy and creating strong surges. The confined space can lead to dangerous conditions, with waves crashing violently inside.
   • Considerations for Coasteering: It is essential to assess swell conditions before entering sea caves or arches. During large swells, it is safer to avoid these features due to the risk of being trapped or injured by powerful surges.
4. Tidal Pools and Sheltered Bays
   • Impact of Swells: Sheltered areas such as tidal pools and small bays can provide respite from large swells, as they tend to dissipate wave energy. However, strong swells can still create unpredictable surges within these areas.
   • Considerations for Coasteering: These areas can be safer for beginners, but guides should still monitor for unexpected surges, especially when swells are large and tides are changing.
5. Boulder Fields and Intertidal Zones
   • Impact of Swells: The interaction of swells with boulder fields and intertidal zones can create complex wave patterns and strong currents between the rocks. Swells can cause significant water movement, making navigation challenging.
   • Considerations for Coasteering: Coasteerers should move carefully through boulder fields, paying attention to the timing of waves and the movement of water between rocks. These areas require good balance and agility.

Practical Applications for Coasteering Guides

1. Assessing Swell Conditions:
   • Forecasting Tools: Use reliable swell forecasting tools and apps such as Surfline or Magicseaweed to assess incoming swell size, period, and direction. This information helps in planning safe routes and timings.
   • Local Knowledge: Familiarize yourself with how different swell directions and sizes affect the specific coastal area. Local knowledge can provide insights into which formations are safe under various conditions.
2. Route Planning:
   • Avoid High-Risk Areas: During large swells, avoid routes that involve cliffs, steep rock faces, and sea caves. Opt for more sheltered routes with less wave impact.
   • Timing: Plan routes to coincide with lower swell periods and slack tides to minimize the impact of waves and currents.
3. Monitoring and Adaptation:
   • Continuous Monitoring: Keep an eye on the ocean conditions throughout the coasteering session. Swell patterns can change, and it’s essential to adapt the route if conditions become unsafe.
   • Emergency Exits: Identify and communicate emergency exit points along the route in case conditions deteriorate rapidly.
4. Safety Precautions:
   • Protective Gear: Ensure all participants wear appropriate safety gear, including helmets and buoyancy aids, to protect against impacts and help with buoyancy in turbulent water.
   • Group Management: Maintain close group control, with experienced guides leading and trailing the group to assist with navigation and provide immediate support if needed.

Integrating Tide and Swell Knowledge

Practical Application for Coasteering Guides

1. Pre-Session Planning:
   • Check Tide and Swell Forecasts: Use reliable sources such as the Met Office or specialized marine weather services to get accurate forecasts. Windy is a great app to assess various forcasts.
   • Assess Conditions: Evaluate the tidal range and swell size to determine the safety and feasibility of the planned route.
   • Plan Alternates: Have alternative routes or exit points in case conditions change unexpectedly.
2. During the Session:
   • Monitor Conditions: Continuously observe the tide and swell conditions. Be prepared to adapt the route if necessary.
   • Communicate with the Group: Keep the group informed about the conditions and any changes to the plan.
   • Safety First: Prioritize the safety of the group. Avoid pushing the limits in adverse conditions.
3. Post-Session Review:
   • Evaluate Performance: Review how well the session went in relation to the tidal and swell conditions. Identify areas for improvement.
   • Update Knowledge: Stay informed about the latest developments in marine forecasting and coastal safety.

The interplay between tides and swells shapes the coastal environment, influencing every aspect of a coasteering session. With detailed knowledge and careful planning, coasteering can be a brilliant and safe adventure.

Coasteering guide courses:

8-Day Coasteer Guide Training Course in Newquay

Intensive 8-day course, set along the stunning Cornish coastline, is designed to fast-track your entry into the coasteering industry.

NCC Coasteering Guide Award in East Lothian

This professional-level course is ideal for existing coasteering guides seeking the NNC guide award and for those aspiring to become adventure guides.

Further resources:

• Surfline: Swell Forecast
• Magicseaweed: Swell Forecasting
• UK Hydrographic Office (UKHO): Marine Forecasts
• NOAA: Tides and Currents
• Met Office Marine Weather Services: Marine Forecasts