The following information, observations and conclusions are from the perspective of a Saturna Island based Sea Kayaker and Paddle Canada certified Sea Kayaking Instructor and compiled to the best of her knowledge and experience over the past five years.
Tides move up and down, currents move side to side. Tides are actually long-period waves that roll around the planet as the ocean is “pulled” back and forth as the moon and sun interact with earth. The moon orbits earth and earth spins around the sun. The moon and sun both have a gravitational pull, strongly effecting large bodies of water. There is a repeating cycle as the moon orbits earth. The moon causes the majority of the gravitational pull. When sun, moon and earth align during full moon and new moon, the gravitational pull is amplified. Around two days later we experience the largest tides, called spring tides (think of “springing up and down”). This means that more water moves between low and high tides. During the first and third quarter moons, the gravitational pull is reduced, and we have smaller tidal ranges, called neap tides. Currents, also called tidal streams, are the horizontal effect of the tidal movement. While tides are biggest at spring tides, currents are also stronger as more water volume is pulled around earth. Due to the varied coastline and the many small islands in our area, slack water (when there is little to no current at the change of direction of tidal flow) does not necessarily occur simultaneously with high and low tide times, despite their correlation. The West coast of North America mostly experiences two high and two low tides of different heights each lunar day. This tidal pattern is called a mixed semi diurnal tide.
Which tidal station do I look up when paddling off Saturna Island? Primary tide stations that are relevant for Saturna Island are at Fulford Harbour on Salt Spring Island and Point Atkinson between Horseshoe Bay and West Vancouver. Saturna Island has two secondary tide stations: Tumbo Channel and Narvaez Bay and there is also Hope Bay on Pender Island nearby. I once wrote down tide predictions for Hope Bay, Tumbo Channel and Narvaez Bay, Fulford Harbour and Point Atkinson. I converted all the information into a graph and noticed that the difference and potential error margin for our purpose is too small to really fuss about (see graph). Especially when looking at Tumbo Channel, Hope Bay and Fulford Harbour: the graph looked almost identical for those three. Who knows, maybe I just picked a particularly good day to compare them 🙂
Keep predicted tide heights and possible variance due to wind and barometric pressure in mind when leaving your boat at the beach while going for walks or overnighting. Always secure your kayak with a rope too. High pressure systems can contribute to very low tides while low pressure systems can increase the height of a predicted high tide.
The Department of Fisheries and Oceans publishes tabulated printed data annually. You can buy Volume 5 for tidal stations of Juan de Fuca Strait & Strait of Georgia or get Tide information at Fisheries and Oceans. Tabulated data is easy to write down while a graph puts numbers visually into perspective and considers that tide heights increase fastest in the middle two hours between low and high tide (roughly six hours apart); both are useful tools.
Ensure that tide times are in PDT (Pacific Daylight Time) or PST (Pacific Standard Time, which you need to adjust during daylight savings in summer). In Canada, tides are measured in metres. Many websites work in feet and generate graphs which I find easy to relate to my needs. What interests us as when launching and landing a sea kayak in Lyall Harbour, is when the tide is going to be over four to five feet (by Fulford Harbour tide station). We prefer to avoid the otherwise inevitable mud battle. Intertidal zones are illustrated in green colour on nautical charts. Looking at a nautical chart for the area, you will notice how much intertidal zone there is at different beaches (look at Cabbage Island for example). Consider this when choosing launching and landing sites, especially when packing gear for overnight camping trips and dealing with low tides.
Kayaking along rocks with a large visible intertidal zone is particularly beautiful and interesting. Sea stars, sea urchins and other sea creatures, normally hidden, become visible at low tide. Take care when crossing fragile intertidal zones, seaweeds and eelgrass that provide fundamental ecosystems for the Salish Sea.
We have summarised sources of information for tide, weather and currents relevant to Saturna Island.
Use this information for the Go/No-Go decision making process that we use in planning and executing a trip, considering various environmental factors.
Ok, so we have figured out the relevant tide stations. And we understand that greater tide ranges happen at spring tides and smaller tidal ranges during neap tides. If you are looking for less currents, go kayaking during neap tides. If you are looking for more currents to play in, look for spring tides. All this is especially relevant when navigating through small passages like Boat Passage or around Boiling Reef off East Point. Our next article will decode currents around Saturna Island.
KayakingSkills.com offer Paddle Canada Sea Kayaking skills and instructor courses at various levels. We teach essential and relevant sea- man/woman -ship. We promise to educate and entertain you. You will get hands on experience with tides and currents in our courses when planning a sea kayaking trip. We help you identify hazards to avoid and risks to mitigate for your sea kayaking adventures. Our intermediate courses include current clinics in areas such as Boiling Reef, Tumbo Island and Boat Passage.
Happy Paddling!
