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Story: Floods

Rainfall across the Southern Alps

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A depiction of the Southern Alps showing where rain mostly falls.

This cross-section of the Southern Alps shows the enormous variation in annual rainfall within a few tens of kilometres. The highest rainfall – up to 13 metres – occurs in a narrow band west of the main divide. The prevailing westerly winds force moist air from the Tasman Sea over the mountains. As the air rises and cools, much of the moisture condenses as rainfall.

 

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by Trevor Chinn

Source: Trevor Chinn, ‘How wet is the wettest of the wet West Coast?’ New Zealand Alpine Journal 32 (1979): 86

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How to cite this page

Eileen McSaveney, Floods – New Zealand’s number one hazard, Te Ara – the Encyclopedia of New Zealand, https://teara.govt.nz/en/graph/4872/rainfall-across-the-southern-alps (accessed 3 June 2026).

Story by Eileen McSaveney, published 2 March 2009, updated 1 February 2024.