Yesterday I drove north to the Bay of Fundy, the triangle of water that separates the western half of Nova Scotia from the mainland. As the sign proudly informs you when you get within fifty miles of the coast, this is the home of the highest tides on earth.

Tides turn out to be one of those things that grow more complicated the more you learn about them. Luckily, the reason for the extreme tides in the Bay of Fundy is pretty simple. The Wikipedia explains it:

The time it takes for a large wave to travel from the mouth of the bay to the opposite end, then reflect and travel back to the mouth of the bay, coincidentally matches the time from one high tide to the next. The result of this coincidence of timing is that that repeating wave is reinforced by the tidal rhythm, and consequently the world's highest tides are found in that bay.

Resonance, baby! Think Ella Fitzgerald breaking the wineglass, except that Ella is the Moon and the wineglass is a gorgeous triangular bay some fifty miles long.

A couple of sources also mention a 40:1 resonance between the Bay of Fundy and the larger Gulf of Maine system (bounded by the coast and the continental shelf), but I'm not sure what they're talking about.

The upshot is that fourteen cubic kilometers of water commute back and forth between the ocean and the inner bay, twice a day. This is so much water that its weight actually lifts and drops a part of Nova Scotia with it, by an infinitesimal amount.

I wanted to see a place called Cape Split, a west-facing spike of land at the mouth of the Minas Basin, where all of the moving tidal water has to squeeze through on its way in or out. In the hours between high and low tide, there is more water flowing here than through all of the rivers on the planet put together.

The drive up from Halifax is probably beautiful (I saw distant hints of mountains and sea through the sheets of rain), and the number of 'Scenic Overlook' road signs near Wolfville made me envious of people who have seen the bay under clearer skies. To me, it was a diffuse grey mist, with occasional bursts of autumn color peeking through. The hurricane had spent itself before getting this far north - the trees hadn't been stripped bare, and it was still full autumn.

Cape Split itself is a promontory of undeveloped land - there is road access, but the last bit requires a hike along an unmaintained forest footpath. An ominous sign at the trailhead reads:

Hikers are advised to wear hunter's orange between Sept. 15 and May 15.

Instead of safety orange, I was wearing a dark sweater and jeans, and the persistent rain meant that half of me was going to be covered in earth-tone mud. I might as well have been wearing artificial antlers. But there was no gunfire to be heard - always an encouraging sign - and I was feeling lucky.

The sign warned on:

Be advised the hike is four hours long - two there, two back.

Sure, I thought, four hours for an out-of-shape weekend hiker. But without a backpack weighing me down, how long could it take? After all, I'm at the absolute peak of my marathon training. Every muscle in my body is tuned for endurance and speed - I could probably run most of the trail, and slow down only to ford the really muddy parts. Who were these Canadian trail maintaners, to think they could intimidate me?

Four hours later, I emerged from the forest, drenched and exhausted and covered in mud. My hands were so cold that it took me ten minutes to work my car key out of my back pocket, and another five to get in the car and start the the heater working. Shades of Jack London. But I made it.

And the last part of the sign hadn't been an exaggeration:

Prepare to see one of the wonders of nature.

Cape Split is covered in pine forest until its very end, where the trail spits you out onto a giant turf-covered cliff. There are two smaller, inaccessible cliffs further on, and everywhere to the right is an expanse of roaring water, where the tide collides with itself, trying to make its twice-daily appointment with the moon. It is very, very beautiful there, even when your sweater has absorbed your body weight in water, and you know you have to spend the next two hours dodging buckshot in the mud.