“Under NSW government rules, Warragamba is operated as a water security dam. This means it must at all times hold as much water as possible for Greater Sydney’s water supply.

“Stored water cannot be released.”

Homes, businesses without power

Major energy providers are scrambling to restore power in blacked-out and flood-stricken areas following the weekend’s extreme weather.

Essential Energy, the majority energy provider for the region, said on Monday morning more than 18,000 homes and businesses were without power across the Mid North Coast and New England regions.

As of 9am Monday, the following communities are the most impacted:

A spokesperson said a “large amount of reconstruction” work was required but crews were hoping to make progress on Monday weather and access permitting.

“Helicopters and additional crews are ready to come in to support as soon as it’s safe to do so,” the spokesperson said.

“Customers are reminded to keep at least 8m away from fallen powerlines, power poles and damaged electricity equipment or 150m away if any part of the electricity network is covered in floodwaters.”

Those without power were urged to check the outages page for updates on estimated times of power restoration as they become known.

An Endeavour Energy spokeswoman said its network – which provides for much of Western Sydney and the NSW coast south of Sydney – had held up “pretty well” over the weekend, with less than 500 customers without power and those expected to regain electricity within hours.

“Lots of rain but not really damaging conditions. We saw a few lightning strikes and a few short interruptions, which were probably tree branches falling on power lines,” she said.

“With those, our automatic system was able to restore power within 90 seconds.

“Yesterday, we had an incident in Albion Park that had a few hundred customers out for a few hours. And today at 3am we had a large tree fall down at Wiseman’s Ferry. The [State Emergency Service] are up there at the moment, cutting down the tree and then our crews will get to work and we expect that one to be back on by 12 and that’s currently impacting 478 customers.

“Overall our networks held up really strong with the conditions.”

‘Evacuate now’: Warning as towns flood

Residents in parts of NSW are being urged to evacuate or prepare to be isolated as floodwaters sweep through the state.

Authorities are expected to resume their search for a 26-year-old woman swept away by floodwaters in the Hunter Valley on Saturday.

People in parts of Gunnedah and Raymond Terrace were told to evacuate on Sunday evening by the SES.

“You must evacuate now because inundation is occurring and evacuation routes will be closed due to floodwater,” one of the alerts read.

The next updates for both areas are due to be issued later on Monday.

The SES has also issued watch-and-act warnings across vast segments of the Hunter Valley and much of the Namoi Riverlands that connect Gunnedah, Narrabri and Tamworth.

Police have urged members of the public to avoid dangers and hazards like powerlines and flooded roads if they end up in flood-affected areas.

NSW SES Deputy Commissioner Debbie Platz said most of the damage had been caused by severe storms that swept through parts of the Hunter Region, with roofs ripped from homes and fallen trees damaging cars and properties.

“So we’ve had over 1500 amazing volunteers out in the field this weekend, who have responded to over 2000 incidents,” she said.

“Some of those from the severe storms, as I mentioned, on the east coast, [and] some for the severe snowstorm that we had in the Tablelands.

“And now what we’re seeing is some major flooding occurring in some areas of NSW.”

Platz said weather conditions would ease to scattered rainfall today, but rivers and catchments were very full and rising rapidly.

She urged residents to remain alert but not alarmed.

“We are seeing the Hunter River rise very quickly and we have evacuation warnings in place for areas around the Raymond Terrace area, but we have 58 warnings in all at the moment,” she said.

Desperate search for missing woman

Authorities resumed the search for a Hunter Valley woman, more than 30 hours after she was swept away.

Police said the incident occurred after a Mini Countryman had attempted to drive through the floodwater before it became stuck.

“The driver – a 27-year-old woman – was rescued without any injuries; however, her passenger – a 26-year-old woman – was swept away,” police said.

“A multi-agency search commenced for the woman including local police, NSW Rural Fire Service, and VRA Rescue NSW, and continued (on Sunday).”

The search was suspended at 4.30pm after conditions became hazardous but was expected to resume today.

Transport update:

Transport infrastructure across the state is feeling the effects of the weather event with major roads and train routes flooded.

Delivering an update just after 10am local time, a Transport NSW spokesperson confirmed which routes were affected.

“In the state’s north, the Oxley Highway remains closed between Gunnedah and Carroll,” they said.

“The highway is closed between the Kamilaroi Highway and Redbank Rd.

“The New England Highway (Bridge St) has reopened at Muswellbrook following flooding. The highway had been closed between Haydon St and Market St.”

In Sydney, Audley Weir in the Royal National Park remained closed and motorists were advised to avoid non-essential travel in areas affected by severe weather and reminded never to drive through floodwaters.

“In addition to state managed roads, some local roads managed by councils may also be affected,” the spokesperson said.

A limited number of buses have replaced Hunter Line trains between the Newcastle interchange, Scone and Muswellbrook because of flooding on the tracks at Sandgate.

“We expect the line to remain closed until at least midday today. Allow extra travel time,” the spokesperson said.