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Arriving to Go with the Flow

We start our tours with a water taxi ride out to Maurelle Island. We leave from the historic Heriot Bay Inn and cruise up the east coast of Quadra Island until Maurelle’s Dome Mountain appears on the mountainous horizon. Then we duck into Surge Narrows, and that’s when things start getting interesting.  Our commercial water taxi, expertly piloted by an experienced local, suddenly feels quite small as the current rushes around us, the ocean looking more like a white water rapid as it tears past, boiling in front of the boat and whirl pooling on either side. If you look at the shoreline, it’s clear that the ocean through Surge Narrows runs like a river; there is a definite gradient, and water races by ‘downstream’ at an impressive pace. Guests find it hard to believe that this torrent will calm down and in six hours time be running just as fast in the other direction, and that in the window between those direction changes, we’ll take to the sea and paddle through Surge Narrows.

I learned my tide and current theory on one of my guiding courses, sitting in the sand with a SKILS on Vargas Island, north of Tofino. With the wind rifling the pages of the trusty Tide and Current Volume 6 that every West Coast guide knows and loves, my peers and I sat doing the math to work out tidal exchanges, flow rates and slack times in exotic sounding places with some very fast current. Imagine my excitement (and, lets be honest, trepidation) to turn up on Maurelle and find all the places I’d been studying as extreme examples of current written on the chart in the cabana; Surge Narrows, Beazley Passage, Hole in the Wall, Upper Rapids. I was going to be guiding guests through these waters!

Waiting for Slack

The theory behind figuring out a current is relatively simple. Tide is the vertical movement of water; the gravitational pull of the sun and the moon works on water, affecting global sea levels and the tide rises and falls twice each day in most areas. Current is the horizontal movement of water, which ebbs and floods continuously, with a full slack, turn, ebb, turn, slack, flood cycle repeating two times a day. The two are linked but not directly, especially in areas like Surge Narrows, where tides from different areas meet and affect each other.

I wish it were as simple to say that high and low tide is when the current is slack, but there’s a little more to it than that. Ocean currents run from slack, a period of stillness, to turn, when the water changes direction, to maximum, which is when the water is moving at it’s fastest, before the flow rate drops off and the current slows down before the next slack, and turns to flow the other way. If we break the time between turns up into six equal segments, hours for the sake of argument, at the end of the first hour the current is running at 50% of its maximum, the end of the second hour is 90%, and by the end of the third hour the current is at maximum speed. The current dies down in the same way before it turns to flow in the other direction by the end of the sixth hour.

The wonder of Moon Power

The difficult part for me is figuring out when and how long the slack will be, because that’s the best time to get on the water and explore the rich habitat in Surge Narrows. The duration of the slack is affected by wind speed and direction, the phase of the moon, and how close the moon is to the earth as well as the tide. Luckily for me, Brody grew up on this stretch of water, from taking the school boat over to Read Island as a kid to commuting to work in Campbell River by jetski; he knows these waters better than anyone and is always on hand when I’m sitting down at the beginning of the week trying to decide when to take our guests into Surge.

All the study and math paid off the first time I got to take my guests through Surge Narrows, under Brody’s watchful eye, at slack. The water was still and crystal clear, we could see all the way down to the urchin colonies meters below us. Seals frolicked around their rookery, and as we rounded the corner into White Rock passage on a very low tide, we saw shimmering iridescent kelp, spider crabs, and geoduck clams going about their business. One of the guests likened it to snorkelling without getting wet. We timed it so that we turned for home with the current, and got to go with the flow all the way back to base.

Written By: Kat Osei-Mensah