New Zealand lies in the path of a strong westerly airflow known as the "roaring forties", producing strong and regular winds across the country. In the Wellington region the North and South Island mountain ranges funnel winds through the Cook Strait producing the region’s notorious winds.
Effects of a storm
Parts of the region may become isolated by flooding, landslides or even high winds closing roads and other access points. Storms can damage utilities, particularly power lines, or may be the cause of transport accidents.
Historical storms in the Wellington region
Large storms are a frequent event in the Wellington region. Wairarapa's "big blow" of 1934 toppled trees, smashed windows, and demolished buildings. Heavy rains caused both the Waipoua and Waiohine Rivers to flood, resulting in further damage and considerable stock losses. In April 1968 ex-tropical cyclone Giselle caused extensive damage to parts of Wellington, destroying houses in Kingston and removing roofs across the city. The storm caused the TEV Wahine to strike Barrett’s Reef at the entrance to Wellington Harbour with a total loss of 53 lives.
In June 2013 a large southerly, with winds of over 200 km/hour damaged infrastructure including train and power lines. Many large trees around Wellington, Lower Hutt and Porirua were felled by the strong winds.
Frequency of storms
Storms are commonplace in the region, and present a high risk due to their frequency and ferocity.