BEWARE THE PERIGEAN SYZYGY (February 7/03)

While the Acadians of the Minas Basin weren’t aware that alignment of the sun, moon and earth is called a perigean syzygy, their dykes apparently felt the force of this turbulent combination on more than one occasion.

As Ivan Smith pointed out in a letter to this paper last September, there are often disastrous effects when a perigean syzygy coincides with a coastal storm; the damage on these occasions can be far-reaching and devastating.

Mr. Smith had done a bit of meteorological detective work when he wrote about perigean syzygies. In my September 20 column last year I mentioned the great damage to the Acadian dyke system by an autumn storm in 1759, and Mr. Smith wondered if a syzygy was involved.

“Sure enough,” he wrote this paper. “There was a Full Moon syzygy on November 4th, 1759.” The storm practically coinciding with the perigean syzygy created “astronomical forces (and tides) that were exceptionally strong,” Smith said.

I had written in the September column that the 1759 storm had raised sea levels almost two meters higher than usual and a combination of gale winds and high tides smashed Minas Basin dykes. The dykes had been left largely unattended since the expulsion of the Acadians and were in a “state of disrepair.” The state of the dykes, and the storm accompanying the perigean syzygy flooded land the Acadians had farmed for generations and left the Kings and Hants County Planters in a sad state.

Mr. Smith pointed out that another perigean syzygy combined with a storm just over a century later, again creating havoc on the dykelands. This was the so-called Saxby Gale.

Over the centuries the dyked land along the Minas Basin has been at the mercy of the wind and tides. In a paper on the Acadians, Ernest Eaton wrote that “even with the best of care, severe storm action in summer or drifting ice in winter could damage the face of the dykes.” Continual attention was required, Eaton said, to keep the dykes in repair. Eaton noted that on many occasions, a combination of winds and high tides had opened the Acadian dykes; some of those destructive storms no doubt coincided with a perigean syzygy.

Bad luck with the dykes plagued the Planters long after the Acadians had been expelled, and as mentioned the 1759 storm was one of the worst. Almost two years after the great storm of 1759 the dykes were still in disrepair, mainly because the government stalled on paying for repairs.

When first completed the Wellington Dyke was wrecked by a combination of wind and high tides that, which from Ernest Eaton’s description of this storm, may have been the dreaded perigean syzygy. “The last gap was closed in 1832,” Eaton said. “This was the signal for a general celebration but that night a severe storm and high tide washed out the new work and daylight saw the sea again in possession.”

According to Ivan Smith the combination of elements called the perigian syzygy will occur several times in the next decade, and at least five times this year. “None of these is dangerous by itself,” Smith writes. But beware the perigean syzygy if an intense storm arrives at high tide time. Serious damage can then be expected, Smith says.

Perigean syzygies will occur in this region in mid-April and mid-May and in the last three months of the year. Let’s hope no great storms rumble down the Fundy shoreline at this time.

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