Soil moisture levels are already below normal across parts of Canterbury, Otago, Southland and other parts of the South Island.
From late spring into summer FENZ (Fire and Emergency New Zealand) expects:
- More easterly winds than normal, as La Niña strengthens which may result in near- to above-normal rainfall for parts of the eastern South Island, with drier-than-normal conditions across the west and south.
- Prevailing patterns of high pressure may result in longer dry spells, even in the east.
- The frequency of rain days may be reduced right across the island. However, occasional heavy rain events from tropical systems could bring flooding to parts of the South Island, as the risk of an early-season tropical cyclone is enhanced this season.
What this means for fire danger
Another La Niña summer means we may see conditions very similar to the past two seasons, which brought above-normal fire dangers to the south and west of the South Island, and below-normal fire dangers along the east coast.
Although it is still very early in the fire season, the areas of the South Island most likely to experience above-normal or slightly above-normal fire potential over the next few months are again in the south and west (Southland, Fiordland and Westland). Eastern areas (coastal Marlborough/ Kaikoura and Canterbury) are most likely to see below-normal fire potential.
Watch out for:
- areas where grass fuel loads are higher than normal due to good growing conditions and grass curing more advanced than normal due to dead “thatch” layers or frost curing
- elevated FFMCs (Fine Fuel Moisture Code – a moisture content rating that indicates the likelihood of a fire starting)
- warm, dry windy conditions
- property owners undertaking burning – they may be complacent due to the low prevailing fire danger conditions, so escapes may be more likely, especially under windy conditions, and
- flare-ups or re-ignitions of old burns – these may especially occur during periods with strong winds.
This is just a guide, so it is essential, as always, to monitor and respond to local conditions, and please follow all fire-related instructions from Wenita staff.