The Illisarvik drained-lake field experiment (1997; Burn, 2015). Ross drained the oval-shaped, 300-m × 600-m, tundra lake in eight hours on 13 August 1978, to study the effects of permafrost development ab initio. The site, on Richards Island in the Mackenzie delta area, lies at the western Arctic coast. Lake Illisarvik drained out to the Beaufort Sea by thermal erosion of an ice-wedge system, facilitated by thaw beneath a trench, dug earlier in the summer above the ice wedges. Prior to drainage, the bowl-shaped body of unfrozen, lake-bottom sediments, surrounded by permafrost, was 32 m deep, beneath the middle of the lake. The site has been monitored continuously for 40 years, with observations in summer and winter. In Inuvialuktun, the language of the indigenous Inuvialuit, Illisarvik means ‘a place of learning’.