Floods in the Southern Alps of New Zealand: the importance of atmospheric rivers

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Colleges, School and Institutes

External organisations

  • University of Otago
  • European Centre for Medium-Range Weather Forecasts


Extremely high precipitation occurs in the Southern Alps of New Zealand, associated with both orographic enhancement and synoptic-scale weather processes. In this study, we test the hypothesis that atmospheric rivers (ARs) are a key driver of floods in the Southern Alps of New Zealand. Vertically integrated water vapour and horizontal water vapour transport, and atmospheric circulation, are investigated concurrently with major floods on the Waitaki River (a major South Island river). Analysis of the largest eight winter maximum floods between 1979 and 2012 indicates that all are associated with ARs. Geopotential height fields reveal that these ARs are located in slow eastward moving extratropical cyclones, with high pressure to the northeast of New Zealand. The confirmation of ARs as a contributor to Waitaki flooding indicates the need for their further exploration to better understand South Island hydrometeorological extremes.


Original languageEnglish
Pages (from-to)5063-5070
Number of pages8
JournalHydrological Processes
Issue number26
Early online date22 Sep 2016
Publication statusPublished - 30 Dec 2016


  • atmospheric rivers, flooding, New Zealand, precipitation

ASJC Scopus subject areas