Otago Regional Council staff have been activated and will be on duty over Labour Weekend, monitoring streams, rivers and lake levels across the region and updating relevant councils about any forecast flooding concerns.
Expectations of heavy rainfall and the possibility of "unseasonable snow" to lower levels across Otago today has prompted the ORC to reiterate MetService’s call to be prepared.
ORC science and resilience general manager Tom Dyer said a weather front heading north up the West Coast was expected to loop over the Southern Alps and come back down into Central Otago, North Otago and possibly coastal areas, from noon today through to a peak about midnight tonight.
"While the weather has been relatively benign around most of Otago for the past few days, heavy rain is expected, which could cause ponding or minor surface flooding in some areas.
"There is also unseasonal snow forecast to above 600m inland, but there’s potential it could lower to around 400m or less in some areas."
At noon, a MetService heavy snow warning remains in place for the Queenstown Lakes District and Central Otago.
Rain in Otago today is expected to total 30mm-50mm, falling "steadily" at about 5mm per hour.
Mr Dyer said that itself was unlikely to trigger alerts, but the still sodden ground from the flooding on October 3-6 in coastal Otago and some areas inland was the concern.
"The rainfall is likely to sheet off the land directly into waterways, which then poses the problem of accumulation and possible surface flooding."
If travelling today, drivers were likely to experience deteriorating conditions and should consider carrying snow chains, with possible disruptions to their journeys.
While most southern rivers had already peaked during the past 36 hours from the first front, the second front today could again see rivers and streams rise, which could pose dangers for people looking to ford waterways.
"If in any doubt, don’t attempt to cross swollen rivers."
He suggested the rural sector should be considering plans to potentially move stock from low lying areas, and how they could be fed.
He urged anyone with concerns to visit ORC’s Environment Data Portal on the front page of ORC’s website for up-to-date tracking of river levels.
MetService forecast in North Otago and Dunedin was for heavy rain at times for the 15 hours from 9am today to midnight, and there was a likelihood the situation would be upgraded to a warning.
In Queenstown Lakes District, during the 18 hours from 6am today to midnight, there would be periods of heavy rain with amounts approaching warning criteria.
MetService said the rain was likely to fall as heavy snow above 600m, and a heavy snow warning was in place for the Queenstown Lakes District and Central Otago.
In Fiordland, from 8am today to 7am tomorrow, southeast winds may approach severe gale in exposed places, and there was a likelihood it could be upgraded to a warning.
