With a high rainfall, the weather is a regular topic of conversation on the West Coast. Near the coast the annual rainfall is 2,000–3,000 millimetres, and it increases rapidly closer to the mountains. The highest rainfall, more than 10,000 millimetres a year, occurs in a narrow zone on the western side of the Southern Alps above 1,200 metres high.
Not enough rain?
Because of the regular rainfall, many rural houses get their water from roof tanks. A month without rain means that tanks become exhausted and surface reservoirs start to dry up. When tankers are needed to cart water, it’s a West Coast drought.
Flooding is an ever-present threat. A substantial part of the budget of the West Coast Regional Council is spent on building and maintaining stopbanks along the major rivers and monitoring river levels and rainfall.
Although rainfall is high compared to the rest of New Zealand, it often occurs as high-intensity downpours. In the main towns, near the coast, more than half the days each year are fine and without rain. Average annual sunshine hours range between 1,800 and 1,900 – fewer than in Christchurch, but more than in Timaru.
A visitor to the West Coast is immediately struck by the extent of native forest. Although some of the river flats and lowlands have been logged and cleared for farming, a higher proportion of forest cover remains than in other regions.
There are two major forest types:
- conifer–broadleaf forest, which covers the area between the Taramakau and Paringa rivers
- beech and beech–conifer forest, found elsewhere in the region.
The absence of beech forest in the central part of the region – known as the ‘beech gap’ – is thought to be due to the extent of glaciers during the ice ages, which destroyed the vegetation in this area. When the glaciers melted, 15,000–10,000 years ago, the bare land was quickly colonised by conifer and broadleaf trees, because their seed is rapidly spread by wind and birds. In contrast, beech seeds are slow to spread.
Small black sandflies are a common annoyance on the West Coast, and will bite any area of exposed skin. While visiting the West Coast in 1892, Lord Onslow (governor of New Zealand) was badly bitten, but his companion, Richard Seddon (then the local MP) was unsympathetic: ‘Let ’em bite my lord. It is very seldom they get a taste of blue blood, and they will enjoy the luxury.’ Seddon was supplied with repellent, and was delighted to demonstrate that he was not bitten. ‘You see, they won’t touch common blood.’ 1
Because of the large forest area on the West Coast, the abundance of native birds is greater than in most other parts of New Zealand. In general, conifer–broadleaf forest supports larger bird populations than beech forest because it is richer in food sources.
The introduction of predators such as rats and mustelids (ferrets and stoats) has had a devastating effect on bird populations. Some species, such as kākāpō (the flightless native parrot), which were common in the 19th century, have now disappeared, and others have become less common. The Department of Conservation is spearheading projects to protect two populations of endangered kiwi species, each with only a few hundred individuals remaining: the Haast tokoeka kiwi and the Ōkārito brown kiwi.
There are several notable birdwatching areas in the region.
- Ōkārito Lagoon, the largest unmodified wetland in New Zealand, is home to the only breeding colony of kōtuku (white heron) in New Zealand. More than 70 other bird species have been identified there.
- Paparoa National Park, one of the most accessible areas of lowland conifer–beech forest, extends down to the sea and contains a variety of bird life. Species such as bellbird, kākā and kererū live there in winter, and migrate to higher altitudes in summer. The unique Westland petrel colony is just south of Punakaiki.
- Arthur’s Pass National Park, in the heart of the Southern Alps, has a variety of alpine species, including kea (mountain parrots), which often enjoy the company of tourists.