An inventory of rock glaciers in the central British Columbia Coast Mountains, Canada, from high resolution Google Earth imagery

Abstract

Little is known about the presence, distribution, age, or activity of rock glaciers in the British Columbia Coast Mountains of western Canada. Reflecting debris accumulation and mass wasting under a periglacial climate, these rock glaciers describe a geomorphic response to permafrost regimes that may or may not presently exist. An inventory of rock glacier landforms in the eastern front ranges of the Coast Mountains, using high-resolution Google Earth imagery, documented 165 rock glaciers between lat. 50°10ʹ and 52°08ʹ N. The majority of these rock glaciers occur at sites positioned between 1,900 and 2,300 m above sea level, where rain shadow effects and continental air masses result in persistent dry, cold conditions. Morphology and field observation suggest that these features contain intact ice. The rock glaciers occupy predominately northwestto northeast-facing slopes, with talus-derived rock glaciers largely restricted to north-facing slopes. Glacier-derived features outnumber talus-derived features by a ratio of 5:1. Several of the inventoried rock glaciers were located up valley from presumed Younger Dryas terminal moraines, indicating that they formed after 9390 BP. Dendrogeomorphological investigations at one rock glacier record contemporary activity that resulted in 1.3 cm/yr of frontal advance since AD 1674. This inventory is the first to document the presence of rock glaciers in the Coast Mountains and supports preliminary understandings of permafrost distribution in the southwestern Canadian Cordillera.

Identifying and mapping very small (<0.5 km2) mountain glaciers on coarse to high-resolution imagery

“…Given the additional complexity and large uncertainties associated with mapping extensively debris-covered glaciers from remotely sensed imagery, the use of our new scoring system is restricted to largely non-debris-covered glaciers. However, establishing guidelines for the identification and mapping of largely debris-covered and rock glaciers may be possible in the future, building on work such as Charbonneau and Smith (2018), who used Google Earth imagery to produce an inventory of rock glaciers in the central British Columbia Coast Mountains, Canada.…”

“…Given the additional complexity and large uncertainties associated with mapping extensively debriscovered glaciers from remotely sensed imagery, the use of our new scoring system is restricted to largely non-debris-covered glaciers. However, establishing guidelines for the identification and mapping of largely debris-covered and rock glaciers may be possible in the future, building on work such as Charbonneau and Smith (2018), who used Google Earth imagery to produce an inventory of rock glaciers in the central British Columbia Coast Mountains, Canada. Overall, the system allows users to rank units according to specific features and therefore classify glaciers with degrees of certainty, which increases the information on ice bodies within the study area and provides a more objective, repeatable and consistent approach.…”

Spatio-Temporal Distribution of Supra-Glacial Ponds and Ice Cliffs on Verde Glacier, Chile

“…Moreover, Google Earth provides an historical catalogue with sufficient temporal resolution to enable investigation of interannual processes. Google Earth has thus been widely used as a main or supporting tool when performing cryosphere-related inventories, mainly of rock glaciers (Rangecroft et al, 2014;Schmid et al, 2015;Nagai et al, 2016;Charbonneau and Smith, 2018; Jones et al, 2018;Pandey, 2019), but also debris-free (Tielidze et al, 2020) and debris-covered glaciers (Alifu et al, 2016a,b), as well as glacial lakes (Wilson et al, 2018).…”

Digital Image Correlation of Google Earth Images for Earth’s Surface Displacement Estimation

“…In this perspective, the freely and immediately available Google Earth images have supported a number of studies, especially in the context of change detection and mapping application. For instance, the authors of [22] utilized Google Earth imagery to produce an inventory of rock glaciers in the central British Columbia Coast Mountains of Canada. Using a similar methodology, the researchers of [23] mapped 487 glaciers and their corresponding maximum LIA glacial advances in the central Tien Shan of China, analyzing the relationships between the magnitude of glacier changes and local topographic conditions.…”