A surge of Hazard Glacier, believed to have started in 1981, displaced ice as much as 0.7 km. Before the surge, ice thickness was measured by radio echo sounding and temperatures were taken in three holes to the glacier bed. The glacier is subpolar with 10 m temperatures near −5.4 °C, and temperature versus depth profiles show many anomalous features. We attribute these anomalies to various effects of past surges and to ablation at the upper surface. The interpretations are supported by simple calculations derived from dimensional analysis. Part of the glacier is warm based: at two sites the basal temperature was at the melting point; at the third site, upstream from the others, it was −2.70 °C.