HISTORICAL NEWS SEARCH - Government of British Columbia

million m 3 . About 30% of the total volume was contained within the dam on the Zymoetz River. Preliminary velocity
calculations provided estimates of 18-26 m/s along the debris flow. At one location, mud splatter was observed to have
reached 13 m above the trim line, a total distance of about 33 m above the base of the stream channel.
Debris exploded onto the Zymoetz (Copper) floodplain, extending across the river a distance of 250 m, to a
depth of 10-12 m. An estimated 0.5 million m 3 of debris, some rocks up to 7 m in diameter, dammed the river. Water
was backed up on the floodplain 1.5 km. An unknown volume of debris was transported down river. Within 30-45
minutes, the dam was overtopped. During high flows of June and July, the river cut a 5 x 60-m channel through the
dam (Schwab et al.).
Jim Culp, a local fishing guide who has helped the Department of Fisheries and Oceans do an annual count
of Chinook salmon in the river since the 1970s, said the pool extended upstream for about 1.5 km and contained
juvenile fish and adult salmon an steelhead. According to Steve Jennings, fisheries biologist with local firm Triton
Environmental Consultants, it was very difficult to determine long term impacts on the fish stocks. The river later
breached the pile of debris. “It’s fortunate that the river was at high flow because it is moving things along.”
The days prior to the landslide were cool with snow falling at higher elevations. In June, local snow packs
were about 200% of normal. This was reflected in above normal temperature in the preceding months. On May 15, the
Tsai Creek snow pillow station situated at 1,360 m a.s.l. in the Telkwa River watershed wet of Smithers recorded a
snow water equivalent of 1909 mm (Schwab et al.).
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*1) The Copper River landslide is very similar to the one that occurred in 1999 in the Telkwa Pass, about 50 km from
Terrace. That slide also severed the PNG pipeline. Of the four similar rock avalanches in the previous four years in
British Columbia, two have been occurred in the Copper River area.
June 12-18, 2002
Event type: Spring runoff flooding.
Precipitation: Not applicable.
Source: Times Colonist, June 18 and 19, 2002; The Terrace Standard, June 19 and 26, 2002; The Vancouver Sun, June
20, 2002.
A combination of hot weather and rain caused the Skeena, Bulkley, Nechako and Fraser rivers, already
running high from the summer melt of a snowpack that had not as large in 55 years, to rise. Between June 13-15, the
Skeena River near Terrace rose more than 64 cm. On June 16, the river at Usk reached 11.44 m, exceeding the 1999
flood level. Between June 12-18, as the Skeena River spilled over its banks the provincial government opened its
regional emergency response centre in Terrace.
Around June 16, some Old Remo residents fled their homes. That afternoon several homes in the area were
surrounded by water. In Terrace, some Skeena Street and Queensway Drive residents were building sandbag walls to
keep out the water. About a dozen people left their homes in the Old Remo area. Water flooded streets and surrounded
some homes in that area for several days.
In Terrace, floodwaters ate away the riverbank of Rich McDaniel’s Skeena Street home. On Queensway
Drive, generators ran around the clock pumping water from a trailer park on the 1900 block into the Skeena River.
On June 19 in Prince George, the upper Fraser River passed the 9.4-m mark. In south Fort George, the river
breached its bank. The river level there was expected to peak at 9.8 m on June 20 and begin to decline.
At Smithers and Terrace, at least 40 people evacuated 13 homes in anticipation of rising water levels. On
June 20, the Skeena and Bulkley rivers were still very high but receding.
Rain around June 18-19 in the Peace basin raised some rivers to near the top of their banks. Although some
localised flooding occurred, it was not to damaging levels.
Ca. June 22-24, 2002
Event type: Rockslide.
Precipitation: Not applicable.
Source: Schwab et al. 2003.
Sometime between June 22-24, a rock avalanche occurred on Harold Price. A forestry crew doing helicopter
reconnaissance in the area first observed it on the morning of June 24. It was raining hard at the time and high water
flow was observed in the streams. Local snow depths at the time were still around 150-200% of normal for June.
Following the rise to above normal temperatures there was a high discharge in local streams. Prior to the landslide,
temperatures appear to have cooled. During June 22-23, rainsqualls were observed in the vicinity of Harold Prive
valley.
The rock avalanche originated at 1,723 m a..s.l. on the lip of a southwest-facing cirque occupied by a rock
glacier. *1) The total displaced volume was about 1.6 million m 3 . Volume from the upper displacement zone was
estimated at 0.7 million m 3 across a scarp face of 175 m wide by 30 m deep. In addition, an 8-ha area of rubble within
the basin exhibited post slide tension cracks and showed downward and lateral displacement. The volume of the
displaced rock and ice that remained in the basin was estimated in the order of 2 million m 3 . The rock avalanche
dropped 300 m onto the open valley expanding to a width of about 360 m while moving at a rapid speed across a basal
till surface.
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