Assurance MetService gave the most notice possible before yesterday's flash flooding in Wellington.

The record breaking 77-millilitre an hour deluge inundated the Capital from about 4am.

Wellington, Wairarapa and Hawke's Bay south of Tutira still sit under an Orange heavy rain warning until later tonight.

A slip's burst a wastewater pipe in Vogeltown - forcing a household to evacuate.

Victoria University professor James Renwick says MetService uses the best forecasting technology.

He says it's a bit like earthquakes, which are unpredictable, but can be detected as they happen.

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