Many hills around Kamloops look like they have been artificially terraced, with perfectly spaced steps rising from the bottoms to the tops. From a distance the steps look as easy to climb as a staircase, but this impression quickly disappears as you struggle up them. These relief features are known by a variety of names, including terracettes, catsteps, sheep tracks and stock trails. Terracettes are found all around the world but, surprisingly, the cause of terracettes is still a matter of debate.
One of the more unusual theories of terracette formation is that they are created by an elusive creature known as the “side-hill gouger.” This mammal has legs longer on one side of its body than the other and the imbalance results in it grazing in circles around hill tops, gouging out the staircase pattern with its hooves. Since this creature has never been captured or photographed, the theory can probably be dismissed, but post photos with your log if you do see one.
Two main mechanisms are proposed for terracette formation: soil creep and animal (mainly livestock) disturbance. Soil creep occurs when the angle of the hillside is too steep for the soil and other unconsolidated material to remain stable over the underlying bedrock; over time, and with disturbances like freezing-thawing and precipitation, gravity causes this material to slump downhill. If this material slips as blocks, rotating back into the slope, a staircase effect is created. Livestock trampling, particularly in over-grazed areas, is also cited as a main factor, with livestock destabilizing the soil and compacting it into tracks along hillsides as they graze. Other mechanisms proposed include tectonic activity, changes in climate, the interaction of bunchgrasses and soil creep, and the removal of tree roots from previously forested slopes for agriculture, leading to soil instability. In practice, many of these factors probably interact to create terracettes, and terracettes from different regions can have completely different origins.
The staircase analogy is used to characterize terracettes. Like a staircase, terracettes have “risers” (the vertical back of the step) and “treads” (the flat part of the stair you walk on). Terracettes rarely have risers higher than 0.5 m and treads are usually much less than this in width, often 15-30 cm. Around Kamloops, grasses like bluebunch wheatgrass and rough fescue grow on the risers, but the treads are often compacted and bare of vegetation.
I’ve noticed that many cachers around Kamloops avoid Earth Caches, perhaps because they are embarrassed to get the answers wrong. This isn’t an exam! Before you claim the find, send me your answers, even if you’re unsure of them, and don’t post them with your log. The main point is to get out and learn about our local landforms.
To complete this geocache, cachers are asked to:
- Take a photograph of the hillside with your GPS in the foreground (optional).
- Estimate the average height of the risers on the hillside.
- Livestock have grazed in this area for over 100 years. Do you think they are a factor in the formation of these terracettes?
- At the bottom of the hill a 10m section of the slope has slumped. Do you think this instability indicates terracettes would form regardless of cattle grazing?
- (Bonus, optional question). This part of the hillside faces mostly north. Are there terracettes on the north-west face of the hill (by the next turn-off to the south-west) and, if not, why not?
There is a parking area at the 0 km sign of the Lac Du Bois forestry road. I recommend you park there and walk the 300m to the cache site since the main road is actively used by logging trucks. Terracettes may be harder to see in winter but should still be visible.