Hurricanes are known for their destructive winds, flooding rainfall, and the tornadoes they spawn. But it is the storm surge – a wall of ocean water pushed along by the hurricane’s winds – that is perhaps the most deadly. Most of the 172 people killed in Mississippi by Hurricane Camille in 1969 died from the 24-foot storm surge.

Hurricane Earl made landfall over the weekend as a tropical storm in the Bay of Fundy, which separates the Canadian provinces of New Brunswick and Nova Scotia. Minas Basin, on the Nova Scotia side of the Bay of Fundy, holds the record for the world’s largest tidal range: 55 feet between high and low tide.

What causes such extreme tides? It results from a coincidence of timing: the time it takes a large wave to go from the mouth of the bay to the inner shore and back is practically the same as the time from one high tide to the next (about six hours). You can see the same effect in a bathtub full of water if you paddle the water with your hand at just the right frequency.

The potential for extreme tides and storm surge is even greater when a tropical cyclone meets a tidally resonant bay. The highest water level ever recorded in the Bay of Fundy occurred the night of October 4–5, 1869 during a tropical cyclone named the “Saxby Gale.” The high water level – 71 feet – resulted from the combination of high winds, abnormally low atmospheric pressure, and a spring tide. It will interesting to see how Earl’s tides measure up.

WDT’s MyFoxHurricane iPhone app showing Hurricane Earl off the New Jersey coast on its way to the Bay of Fundy.