Winter roads and ice bridges: anomalies in their records of seasonal usage and what we can learn from them

Most believe that the warning of the earth's climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and bridge and rising global average sea level. One possible effect for winter roads and ice bridges in Canada's North is that the mean length of time each road or ice bridge is operationally open will progressively shorten. Tracking the record start- and end-of-season dates and thus the length of season over time for each confirms that - for most cases. But in some cases, the recorded seasonal length has actually increased over time. Global warming will continue to be imposed on Canada. Clearly there are lessons to be learned from the case historis of those winter roads and ice bridges that saw increased seasonal usage. These lessons could be applied to other roads and ice bridges to great benefit, to adapt to the changing climate. This paper provides the detailed statistical record of the seasonal usage of selected winter roads and ice bridges in the Northwest Territories, identifying those cases where the length of the operational season has increased. It then examines what may have caused the lengthening of the seasonal usage of those winter roads and ice bridges, in the face of climate change.