Geomorphic and dendroecological impacts of slushflows in central gaspé peninsula (québec, canada)

Abstract

Slushflows are rare phenomena in southeastern Canada. Here we report for the first time the occurrence of slushflows in a subalpine environment in eastern Canada (Mt. Albert, Gaspé Peninsula, Québec). Because nothing is known of their frequency‐ magnitude in the area, we reconstructed the chronology of slushflow events over the past century using dendrogeomorphic techniques based on impact scars, reaction wood and traumatic resin ducts. Slushflows contributed to the formation of a tongue‐shaped accumulation of 17900 m2 at the outlet of a firstorder drainage basin. The slushflow boulder tongue was composed of heterogeneous‐sized, angular and unoriented clasts, which are markedly different from the sediments of an adjacent alluvial fan. Although movements were initiated above the subalpine forest limit, slushflows induced forest fragmentation along the treed slope. Three slushflow events were identified over the past century, in 1925, 1964 and 1988, respectively, which indicate exceptional initiation conditions and considerable geomorphic activity of individual events.

Geomorphology of snow avalanche impact landforms in the southern Canadian Cordillera

“…(1987) suggest that the minimum ERI value used to determine geomorphic activity should be user defined based on the site(s) under study. High‐magnitude snow avalanche events that excavate sediment from the impact area at the base of the path were identified using a 10 percent cut‐off (Larocque et al . 2001), observing clusters of kill dates of trees, and by determining the establishment age of trees on the track and SAIL.…”

Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues

“…Slushflows are somewhat similar to debris flows in that they contain a low amount of liquid water compared to solids, however those solids are not just sediments but relatively large quantities of snow and ice (> 70%). This leads to a number of differences with debris flows, they can initiate on slopes as low as 10° (Elder and Kattelmann, 1993) (Figure 18a), and although they can have lateral levees, the deposits tend to be chaotic with no clearly defined downslope boundary (Larocque et al, 2001). Like debris flows they can occur in a hillslope or torrent-fan system (Figure 18b).…”

Dendroecological Dating of Geomorphic Disturbance in Trees

“…In avalanche research, index values ranged from 10% (e.g. Larocque et al 2001;Reardon et al 2008) to 40% (Butler and Malanson 1985;Muntan et al 2009), with the latter being suitable for the identification of extreme events. In debris-flow research, Kogelnig-Mayer et al (2011) and Procter et al (2012) proposed the use of a weighted index (W it ) for which the number of GDs, their intensity, number of trees available as well as the intraseasonal timing of GDs are taken into account.…”