Landslide
memories timely reminder
By Nick Anning
Benoit Lafond, owner of Ben’s Towing
in Chelsea, reflects on the 1973 Chelsea
landslide. Tonnes of liquified mud and rock
missed his land by a few metres, but left
a grey scar everywhere.
Thirty-five years ago this week Benoit
Lafond was in the process of establishing
Ben’s Towing business on Hwy 105 in
Chelsea. Two houses south of Ben’s
yard Hector LeBlanc was preparing to move
into his new Chelsea home.
Rising above these two men, about 300
metres west, contractors were close to finishing
the extension of Hwy 5 from Mont Bleu in
Gatineau to Scott Rd.
On the afternoon of Tuesday, May 8, 1973,
as Lafond approached his land, he noticed
a car heading south on Hwy 11, (now Hwy
105), its windshield covered in mud.
Curious, he turned into his yard, to be
met by an almost surreal sight.
The leaves on the trees, along with everything
else before Lafond’s eyes, were covered
by an ugly grey smog.
And in the sky directly above him were
three helicopters, circling.
The reason for this unusual scene, Lafond
discovered, was a dramatic landslide triggered
by workers building the Hwy 5 extension.
An incident, according to both Lafond and
LeBlanc, which could have been avoided.
The helicopters were scouring the debris
for victims.
As it turned out, no injuries were sustained
by the mass of rubble that poured down the
creek literally a few metres from Lafond’s
garage.
In his mind the driver of the mud-splattered
car was the luckiest person alive that day.
“He just made it,” said Lafond
recalling the fateful day. “Thirty
seconds later, he would have been killed.”
He wasn’t the only person lucky
to survive the ordeal.
According to an account of the landslide,
given by Bruce Lister in Up the Gatineau!,
the contract workers building te new highway
only just escaped with their lives.
From late January 1973 they had dynamited
rock from gorges and filled an adjacent
bog with aggregate weighing around 100,000
tonnes. Beneath the bog were nine metres
of deposited marine clay, among it, said
Leblanc, the “very unpredictable leda
clay,” which is about 50 per cent
water.
On that May 8, a bulldozer worker observed
cracks, then a crater ,appear in the new
roadbed. The workers dashed 60 metres to
safety on a rocky outcrop before witnessing
a 10-metre deep crater swallow up the bulldozer,
a truck and other construction gear.
Without warning, rocks, mud and partially
liquefied leda clay, all fed by the spring
runoff, hurtled down the stream valley,
picking up trees, bushes and a few old tires
from Ben’s Towing on the way.
The debris destroyed what was then Hwy
11, carved a notch under the railway tracks
and dumped a mass of mud and rocks into
the Gatineau River at Horseshoe Bay (just
south of Peter’s Point).
According to LeBlanc, a 40-metre stretch
of Hwy 11 was washed away, and the pounding
rocks gouged an 18-metre-deep hole in the
highway.
On May 11 engineers tried to reduce the
pressure on the Hwy 11 embankments by digging
a shallow trench, but it caused more liquefied
mud to surge out of control toward the river.
It resulted, as Lister explains, in a
20-metre chasm under the railway line opening
up, and “the rails, with ties still
attached, hung like a jungle rope bridge
across it.”
Back at the source, 50 metres of newly laid
Hwy 5, about 100 metres north of where the
Chelsea cell tower stands today, was obliterated.
While workers set about rebuilding the
highways, there was some speculation the
landslide should never have occurred.
Leblanc said the contractor “kept
on spreading rock and earth,” rather
than put in a culvert. From his experience
working in the construction business, if
a culvert had been put in first, the landslide
“probably wouldn’t have happened.”
Lafond reinforced this view, stating that
an engineer at the time had said the contractor
“must put a culvert in.”
The memories of 1973 offer a stark reminder
of the risk of leda-clay landslides today.
Two roads in Chelsea, including a section
of Hwy 105, have suffered partial collapse
since April 28. They are both closed until
further notice while awaiting advice from
engineers.
After the 1973 incident, Hwy 5 workers
did put a proper culvert in and finished
the extension to Scott Rd.
Hwy 11 remained closed for six weeks,
allowing LeBlanc and his wife Louise to
not only move in, but live in “peace
and quiet” while northbound traffic
was rerouted via Old Chelsea and Scott Rds.
The railway track and embankment were
restored by fall 1973, although the train
did not run until a year after the landslide
in May 1974.
Through it all Lafond, still able to access
his land, “never stopped working,”
albeit with a little more mud on his hands
than usual.
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