It has been inferred that the scabland in the western head of the Wright Valley was carved by a catastrophic flood from greater deglaciation of Antarctica than formerly postulated. This anomaly, and the anomalous deuterium and solute contents of the water in Lake Vanda, can be explained if volcanic eruption occurred under the thick ice west of Wright Valley. Moving down the valley, the volcano-melted floodwater would fill the Lake Vanda basin. It would be low in deuterium and have a much higher content of solute than ordinary glacial meltwater.