HISTORICAL NEWS SEARCH - Government of British Columbia

concentrated on the Bear River Pass Road and on engineering structures at the Bear River Delta. Cost of
reconstruction and remedial action had reached about $150,000 by 1963 (Mathews 1965).
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*1) About August 13, 1962, the lake broke out under the ice for the fifth known time (Mathews 1965).
October 29-31, 1961
Event type: Flooding and landslides.
Precipitation: Aiyansh (84.8 mm/2 days), October 29-30, 1961; Falls River (95.3 mm/1 day), October 30, 1961; Prince
Rupert M. Circ (102.4 mm/1 day), October 30, 1961; Prince Rupert (72.2 mm/2 days), October 30-31, 1961; Stewart
(152.4 mm/2 days), October 30-31, 1961; Prince Rupert (47.8 mm/1 day), October 31, 1961; Terrace (48.3 mm/1 day),
October 31, 1961.
Source: Prince Rupert Daily News, October 31, November 1, 1961; Terrace Omineca Herald, November 1, 1961;
MAST Ship Listing 1946-1983; Lewis and Moran 1985; Environment Canada 1991.
On October 29, the maximum wind was 55 kn. (102 km/h). The number of MAST observations of winds
over 48 kn. (89 km/h) was two (Lewis and Moran 1985). The storm affected the rail, road, and telephone links. The
telephone line between Terrace-Kitimat was cut. In the evening of October 31, Prince George was hit by winds gusting
to 80 mph (128 km/h). A power pole was toppled in front of the Civic Centre, delaying the traffic.
Highway 16 was closed by slides and flooding. On October 30, west of Terrace, four bridges washed out. A
slide measuring a length of 60 ft. (18 m) and a depth of 8 ft. (2.4 m) occurred near Kwinitsa. A bridge approach 12 mi.
(19.2 km) west of Terrace washed out and further damage occurred. The highway was flooded near Prudhomme Lake.
On October 31, the Zymoetz River near Terrace recorded an instantaneous maximum discharge of 17,500 cfs
(495.5 m 3 /s (Environment Canada 1991). On Highway 16 east of Terrace, the bridge near Hazelton was damaged and
a 6-ft. (1.8 m) culvert was swept from its moorings. Washouts occurred at points 10 and 12 mi. (16 km and 19.2 km)
east of Terrace. In one location, 150 ft. (45 m) of a full width of highway washed away. The Terrace Ministry of
Highways Road Superintendent Carl Shaw stated, “I have never seen so much water come down so fast in all my
experience.” He felt sure that 10 in. (250 mm) of rain had fallen in 48 hours (Terrace Omineca Herald).
On the rail line between Prince Rupert-Terrace, a 20 ft. (6 m) long washout occurred at Mile 10.2, 10.7, and
three other places between Mile 12-13. On November 1, both the highway and rail line reopened. On November 1,
crews were still working in the Kwinitsa slide area. On the rail line between Terrace-Kitimat, a mudslide occurred at
Mile 25.9.
December 26-28, 1961
Event type: Glacial outburst flood.
Precipitation: Not applicable.
Source: The Daily Colonist, December 29, 1961; The Province, December 2, 1965; Mathews 1965 (pp. 46-52);
Mathews 1973 (pp. 99-110); Mathews and Clague 1993.
Summit Lake, north of Stewart, suddenly drained southward under the ice, creating a catastrophic flood in
the Salmon River. The water forced its way south under Salmon Glacier for a distance of 8 mi. (12.8 km) into the
Salmon River. From the time of the first surveys, around the turn of the century, Summit Lake had drained northward
into the upper Bowser River. This lake, impounded by Salmon Glacier, is the largest self-draining, ice-damned lake in
Canada (Mathews and Clague 1953). In the many self-dumping lakes in northern British Columbia and Alaska, the
dumping process usually occurs in summer at the height of the melting season.
Of this first jökulhlaup event from Summit Lake under Salmon Glacier near Stewart, in its 60 years of
recorded history, only the flood of Salmon River below the glacier was witnessed. The Nine Mile bridge across the
Salmon River had part of the bridge deck carried away. The steel-truss bridge that provided access to local mineral
prospects in Alaska was written off. (Mathews and Clague 1993). The structure was finally destroyed in 1967
(Mathews 1973).
Though the river was reported to have been unusually muddy as early as December 22, eyewitness accounts
indicate that the flood began about December 26. The river rose rapidly on December 27, cresting in the afternoon of
December 28, at which time it was choked with icebergs. On the afternoon of December 29, the river subsided rapidly.
By 4 p.m. that day the river was down almost to normal winter flow, though it remained muddy.
At the time of the flood, nobody observed the lake. A few days later, it was checked and found empty. At the
time the draining started, the volume of the lake was estimated to have been 5-6 billion ft. 3 (141-170 million m 3 ), most
of which was discharged in three days. The mean discharge during this period can be computed at somewhat more
than 20,000 cfs (556.3 m 3 /s), with a peak discharge at perhaps twice as much.
The flooding caused heavy damage to roads, bridge, and protective works along the riverbanks and delays
and inconvenience to mining activities upstream. The total cost could not be reliably appraised, but full restoration of
all services may have exceeded $200,000. Though Summit Lake itself was not observed during the flood, an aerial
survey conducted a few days later found the lake to be empty except for scattered icebergs. One observer reported a
tunnel entrance at the southwest corner of the lake, through which the water apparently had escaped (Mathews 1965).
*1)
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