Today, on a remote section of the Fraser River west of Clinton, tens of thousands of salmon are roiling around in turbulent pools, most of them unlikely to ever make their way upstream to spawn. The fish are trapped below a 5-meter cascade, caused by a rockslide that crashed into the river near Big Bar in late June.
It’s not the first time.
With almost 2,000 kilometers of mainstem river meeting thousands of tributaries, the Fraser and Thompson River systems have seen countless landslides over the millennia. Oral histories from Indigenous people throughout the interior contain intriguing details of rivers damned by sticks, rocks, and ice, at times maintained, or eventually destroyed, by supernatural beings.
Combining evidence at macro and micro scales, archaeologists and geologists have been able to piece together the results of a few such events in the ancient past. One well-known example is a series of slides on the Fraser River about 300 kilometers above Vancouver, near a small tributary called Texas Creek.
While the exact timing and effects of the Texas Creek slides is still the subject of debate, the 1-kilometer long scar the landslide left behind hints at the enormity of the event.
We know that the slide happened sometime around 1,000 years ago, and was believed to have been large enough to impound the Fraser River behind a 45-meter high dam of rock, creating a lake over 30 kilometers long in the Lillooet area. That dam likely persisted for a few years or even a few decades, until powerful flow of the Fraser eventually eroded it away.
Even a blockage of a few years would almost certainly have devastated many salmon runs, and the people who depended on them. The inability of migrating fish to reach their spawning grounds throughout the Interior Plateau would have lasting effects on peoples’ reliance on salmon as a stable and abundant food supply.
The effects of the Texas Creek slide would have affected not only the St’at’imc ancestors in the immediate vicinity of the slide, but also those in the upper reaches of the Fraser system, and eventually, all those in the Fraser basin who relied on the fish.
While archaeologists debate the extent of the cultural effects of the slide, it very likely triggered regional population movements as people reorganized around new food sources. Minimal archaeological evidence of conflict from these movements suggest that strong kinship and trading networks may have eased the shift for those who found themselves without this vital food source.
More recent examples corroborate some of the theories about the Texas Creek event. A slide on the Bulkley River near Hazelton in 1820 created a stretch of rapids that impeded salmon, and Wet’suwet’en families moved their village temporarily from Moricetown to below the obstruction.
In 1913-14, railway work in the lower Fraser triggered a series of massive slides at Hell’s Gate, blocking the already-constricted canyon and causing a catastrophic crash in salmon populations. Ladders to get migrating fish over the slide were not built until 1945, and stocks have still not fully recovered to pre-slide levels.
Clearing Hell's Gate Rockslide, Fraser River ca. 1916, Vancouver Public Library
While the 2019 slide at Big Bar is a natural, even regular occurrence on the landscape, it has come at a time when salmon stocks are critically low due to overfishing, industrial pollutants, and warming waters.
Huge numbers of salmon that would normally get funneled into the Interior Plateau won’t make it home, and so won’t spawn, and the people and animals who depend on them for food will suffer even greater shortages in the years to come.
Massive, even heroic, efforts are being made at that site to help the fish. But like never before, time is of the essence for BC salmon.