The Largest Tidal Bore in the World - Well, Maybe North America

In a prior blog entry titled, "Riding the Wild Bore", we told about a great rafting trip on the tidal bore.  On Saturday, August 11, 2018, we drove out to the tidal bore viewing center in Truro to see what is billed as the highest tidal bore in North America on the Salmon River.  (The highest tidal bore, up to 9 meters high, is said to be on the Qiantang River in China.) 

Like so many others, we got there an hour early.  With time to kill, we staked out a good viewing spot and had a picnic lunch:

Others also found their spots along the banks of the Salmon River:

The Salmon River empties into Cobequid Bay, which itself is a narrow arm of the Minas Basin.  Minas Basin, in turn, is a narrow arm of the Bay of Fundy.  So, as the bore tide rises in the Bay of Fundy, it funnels upstream into narrower and narrower bodies of water.  This causes an acceleration of the tidal flow and created a powerful surge, which becomes a wave as it encounters the current flowing down against it.

This is how the river looked before the bore tide arrived.  Over half of the broad riverbed was sandbar, and the water itself flowed mainly on the near side.

Here comes to bore tide.  See the whitewater wave as it curls up the river toward us?

This was a great viewing spot, because we could see the wave turn a corner on the river and come rushing right at us:

Straight across from us, it made a rushing sound as it surged past.  We wouldn't have wanted to be in the water at that time because the currents were so strong.

Notice the waves pushing up behind the leading edge.  These are called, "whelps." Once the first wave hits the downstream current and creates the whitecap, the whelps behind it simply surge over the downstream current, making more subtle undulations:

The tide rushed past us and on up the river:

To see a video of the entire event, click here.

Here is a photo after the bore rushed in.  There is no evidence of a sandbar.  The river stretches across its full, wide bed and has risen several feet toward where we stood:

Our next few stops will include stays near the Bay of Fundy itself, where we plan to explore other facets of the tidal bore.  We hadn't expected this dramatic preview, but it'll help us understand what we see out in the Bay itself.