A lake forms last night behind the Dart Valley landslip.
Photo from GNS Science/GeoNet.
All trampers have been accounted for and confirmed safe
after the Dart River was blocked by a massive valley landslip
at Sandy Bluff, about 10km above Chinamans Bluff.
The landslip crashed down about noon on Saturday, authorities
said, and they warned it posed hazards for trampers, campers
and boat enthusiasts.
In a joint statement yesterday, the Department of
Conservation (Doc) and the Queenstown Lakes District Council
ordered everyone to stay right out of the danger zone.
GNS scientists from Dunedin and Wellington were attempting to
assess the landslip and potential hazards by helicopter
yesterday afternoon, but were hindered by poor weather
conditions, before successfully flying in the evening.
Doc conservation services senior ranger Richard Kennett, of
Glenorchy, reported extensive flooding at Dredge Flat,
upstream of the slip. Trampers were having to detour 2km
through forest to get around flooded parts of the track.
''Doc is strongly advising people to defer planned tramps on
the Rees-Dart circuit until the hazard has been fully
assessed and more information is available,'' Mr Kennett
Harbourmaster Marty Black said boat enthusiasts, kayakers and
other recreational users should stay right out of the Dart
River until further notice.
While the Dart River's flow has dropped to minimal levels
because of the damming effect upstream, there is a risk
growing pressure behind the debris dam will breach it,
creating a massive surge of water. This presents a constant
danger for anyone in the river bed below.
Mr Kennett yesterday afternoon said the water was visibly
rising in volume by the hour. By last night the flooding had
spread across and up the valley.