Tasman Lake is a proglacial lake formed by the recent retreat of the Tasman Glacier in New Zealand's South Island.
In the early 1970s, there were several small meltwater ponds on the Tasman Glacier. By 1990, these ponds had merged into Tasman Lake.
Tasman Lake has quickened the retreat of the Tasman Glacier. Initially it did so by undercutting the cliff at the end of the glacier, causing parts of the cliff to fall into the lake. Now, however, a 50–60 m apron of submerged glacial ice projects out from the cliff, and icebergs periodically break off the apron and float away down the lake. Because more of the glacier is now in contact with the water, its rate of retreat has increased. By 2008 the lake was 7 km long, 2 km wide and 245m deep. It is expected to grow to a maximum length of about 16 km within the next one or two decades.
Tasman Lake, the glacier and the surrounding mountains are part of Mount Cook National Park. Taking a boat tour among the icebergs on the Tasman Lake is now a popular tourist activity.
Like many other geographic places in both New Zealand and Australia, it is named after Dutch explorer Abel Janszoon Tasman.
Aoraki/Mount Cook National Park is in the South Island of New Zealand near the town of Twizel. Aoraki/Mount Cook, New Zealand's highest mountain and Aoraki/Mount Cook village lie within the park. The area was gazetted as a national park in October 1953 and consists of reserves that were established as early as 1887 to protect the area's significant vegetation and landscape.