The Royal Canadian Mounted Police has confirmed the death of a snowmobiler near Cabin Lake, in the Nicola Valley about 56 km to the southwest of Merrit in British Colombia. The as yet unnamed man was one of two snowmobilers hit by the avalanche, slightly after midday on Saturday 4 January 2020, and was buried beneath the snow, where his friend was unable to locate him. He was eventually located with the help of a police rescue team, but had died by this time.
The approximate location of the 4 January 2020 Cabin Lake avalanche. Google Maps.
Avalanches are caused by the mechanical failure of snowpacks; essentially when the weight of the snow above a certain point exceeds the carrying capacity of the snow at that point to support its weight. This can happen for two reasons, because more snow falls upslope, causing the weight to rise, or because snow begins to melt downslope, causing the carrying capacity to fall. Avalanches may also be triggered by other events, such as Earthquakes or rockfalls. Contrary to what is often seen in films and on television, avalanches are not usually triggered by loud noises. Because snow forms layers, with each layer typically occurring due to a different snowfall, and having different physical properties, multiple avalanches can occur at the same spot, with the failure of a weaker layer losing to the loss of the snow above it, but other layers below left in place - to potentially fail later.
Diagrammatic representation of an avalanche, showing how layering of snow contributes to these events. Expedition Earth.
Avalanche Canada have issued Extreme Avalanche Danger warnings for much of southern British Columbia this week, as the area has been battered by a series of storms, bringing with them high snowfall levels and fluctuating temperatures, which are considered high risk factors in avalanche prediction. These storms in turn can be linked to an El Niño weather system that has developed over the Pacific Ocean this year.
Current avalanche warnings for southern British Columbia, and neighbouring parts of Aberta. Avalanche Canada.
The El Niño is the warm phase of a long-term climatic oscillation affecting the southern Pacific, which can influence the climate around the world. The onset of El Niño conditions is marked by a sharp rise in temperature and pressure over the southern Indian Ocean, which then moves eastward over the southern Pacific. This pulls rainfall with it, leading to higher rainfall over the Pacific and lower rainfall over South Asia. This reduced rainfall during the already hot and dry summer leads to soaring temperatures in southern Asia, followed by a rise in rainfall that often causes flooding in the Americas and sometimes Africa. Worryingly climatic predictions for the next century suggest that global warming could lead to more frequent and severe El Niño conditions, extreme weather conditions a common occurrence.
Predicted changes to North American weather patterns during an El Niño event. NWS/NCEP Climate Prediction Center/NOAA.
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