Dry conditions worsening, spreading - NIWA report

There's little good news for farmers in the latest report on soil moisture across the country, with very dry conditions expected to worsen and spread.

Many regions are already experiencing 'pre-drought' conditions, including Northland, Waikato and parts of Canterbury.

A weekly soil moisture report from NIWA which assesses severely to extremely dry conditions, shows no improvement in already dry regions, while new 'hotspots' have been identified.

Hotspots are areas with soil moisture deficits, with persistent hotspot regions having the potential to develop into drought.

NIWA said the dry conditions across the North Island continued, with most locations receiving less than 15 mm of rainfall in the past week, particularly in northern areas. 

"This led to additional soil moisture decreases across a majority of the North Island, although an onshore flow has delivered more substantial rainfall and slightly improved soil moisture conditions to Hawke's Bay in recent days," said the report. 

Nelson is among the areas feeling the effects of a lack of rain.
Nelson is among the areas feeling the effects of a lack of rain. Photo credit: Getty

The driest soils across the North Island, when compared to normal for this time of the year, were found across Northland and northern Waikato. While the wettest soils for this time of the year are located near Taupo and Kapiti Coast.

A very large hotspot continues to cover nearly all of Northland, Auckland, northern Waikato, and the Coromandel Peninsula. 

Additional hotspots are in place across most of Wairarapa, East Cape, and central Manawatu-Whanganui.

Dry areas were also worsening across the South Island.

NIWA said there was very minimal rainfall across the South Island in the past week, in eastern areas, while more substantial rainfall occurred along the West Coast. 

"This resulted in nearly universal soil moisture decreases, with the largest losses observed from Tasman to southern Canterbury. 

"The driest soils across the South Island compared to normal for this time of the year are located in coastal Hurunui District as well as interior Selwyn and Ashburton, while the wettest soils for this time of the year include Stewart Island, southern Southland, and Clutha District," it said.

The report said hotspot coverage had expanded substantially across Canterbury during the past week, and now covered from coastal Hurunui District south to approximately Waimate District.

The outlook looks bleak for farmers hoping for a reprieve, with only a small amount of rain predicted.

"With meagre rainfall expected in much of the North Island, widespread soil moisture decreases are expected to continue. 

Existing hotspots are anticipated to strengthen and expand, although conditions may not change significantly in Wairarapa. Meanwhile, higher rainfall amounts may lead to soil moisture increases in Hawke's Bay and Gisborne."

Very minimal rainfall amounts were also expected in the South Island.

"In fact, many locations may receive no rainfall in the next seven days, with only a few places seeing up to 5 mm."

The report said much of Canterbury will be covered by a hotspot, which could also reach southward into interior Otago. 

"Additionally, new hotspots are likely to emerge across Nelson and Marlborough."