An “extended period of significant heavy rainfall” is forecast for Canterbury this afternoon and severe gale southeasterlies along the South Island west coast.

Metservice has issue a “Red Warning for Heavy Rain” for the region south of Amberley, and an Orange Warning for Heavy Rain is in force for the region from Amberley to Kaikoura.

MetService Meteorologist Lisa Murray said “this is only the second Red Warning MetService that has been issued since the colour coded system was introduced mid-2019.”

“The first Red Warning was issued in February 2020 and caused significant impacts including roads being washed out trapping about 1000 people in Milford and rivers bursting their banks causing significant flooding in Southland.”

Murray advises that, “Apart from the Red Warning for Canterbury there is other significant weather around the country which people should be aware of including thunderstorms, wind, snow and swell.”

Dangerous river conditions and flooding are expected.

Blue Skies Weather Forecaster Tony Trewinnard said a narrow feed of strong easterly winds into Pegasus Bay briefly between midnight and 6am Sunday morning is concerning as it coincides with a high tide (around 6am) and the area is likely to have already received 50mm of rain.

“Significant easterly swells will be generated. The potential impact on river/lagoon mouth drainage and possible erosion potential in that brief time period must be concerning.”

Slips and floodwaters are likely to disrupt travel, making some roads impassable and possibly isolating communities.

People are advised to keep up to date with the latest forecasts in case further areas are added, or any changes are made.

Metservice said this rain is expected to cause dangerous river conditions and significant flooding.

Slips and floodwaters are likely to disrupt travel, making some roads impassable and possibly isolating communities.

Expect 200 to 300mm of rain to accumulate about the Canterbury High Country and foothills from 3:00pm Saturday to 11:00am Monday, with 80 to 120mm of rain farther east about the Plains and coast.

Heavy Snow is expected above the freezing level throughout the event, but heavy snow may fall as low as 1000 metres in some places at times, especially today and on Monday.