Australia Weather News

Thousands of people are without power across South Australia and Adelaide's CBD has been plunged into darkness as a massive storm lashes the state.

There are reports traffic lights and Adelaide Metro have said trams and some train lines have been left out of action due to the widespread power outage.

About 5,000 homes are without power.

Adelaide Metro said trains on the Seaford and Tonsley trains were not running.

Earlier in the day, wind gusts of 83 kilometres per hour slammed Port Augusta at the top of the Eyre Peninsula.

Strong winds associated with thunderstorms have rolled in from the Nullabor in the state's west to the Eyre Peninsula (EP), while Kangaroo Island has also recorded a 78kph gust.

The Bureau of Meteorology (BoM) said the thunderstorms moved in ahead of more significant storms that will hit the EP's south this afternoon, and will also affect the Upper EP and the mid north.

A thunderstorm produced large hailstones at Cleve and 14 millimetres of water in 15 minutes on the EP along with an 87kph gust of wind.

BoM's updated severe thunderstorm warning said the system was likely to produce "destructive winds of up to 140kph" and heavy rain that may lead to flash flooding at locations such as Whyalla, Clare, Maitland, Hawker and Leigh Creek.

Severe thunderstorms are also forecast for Adelaide and the Mount Lofty Ranges.

Lightning has struck across the state ahead of a cold front, including in Adelaide where a tree at Myrtle Bank was struck down by a bolt.

Myrtle Bank resident Emma Altman said the tree fell into her house.

"The tree seems to have exploded and come down into the house taking another tree with it," she said.

"It's gone through our kitchen windows and through a bedroom and taken down the fence."

Front to arrive in Adelaide late afternoon

The front is moving in a line from Kimba to Coober Pedy and is expected to arrive in Adelaide at about 6:00pm, even though winds and rain have already hit the city and are expected to continue.

"Strong to gale-force winds averaging about 50 to 65 kph, with gusts between 90 and 100 kph, are expected to develop behind the front," BoM said.

Worsening conditions, however, are due to arrive overnight and into Thursday morning, when an intense low pressure system moves in ahead of massive, 10-metre swells forecast for the West Coast.

It will bring strong to gale-force winds of up to 120 kph on the coast and exposed areas, along with squally showers and thunderstorms.

Locations forecast to be particularly at risk include Ceduna, Coober Pedy, Wudina, Woomera, the Nullarbor and Tarcoola, but there is a chance the system could drop south and affect Adelaide as well.

A flood watch is in place for the Mid North, Mount Lofty Ranges and Adelaide metropolitan districts, and comes just two weeks after homes across the Greater Adelaide area were flooded by burst rivers and creeks.

Rainfall totals from the low-pressure system are expected to be between 30 to 60 millimetres "with some falls of 50 to 100mm possible", the bureau said.

Strike teams on stand-by ahead of severe front

SES spokesman John Carr told 891 ABC Adelaide that Whyalla and Port Augusta has been localised flooding and crews in Adelaide had received the "odd job" but the worse was still to come.

SES chief officer Chris Beattiesaid the biggest risk to lives during the storm would be car accidents.

"This winter we've had a number of rescues in South Australia from vehicles that have become stranded and we've seen a number of vehicles washed down creek systems," he said.

He said the severe storm conditions would place "extreme strain on local response capacity but we have done pre-planning around our ability to surge".

"We've got four strike teams on standby from the Metropolitan Fire Service," he said.

"We've got strike teams on standby from the Country Fire Service. We have two strike teams being made available to us from Western Australia that are currently inbound and we're looking to have them infield, on operations tomorrow."

He said hydrologists and bureau forecasters were keeping a close eye on the Onkaparinga, Angas and Bremmer catchments, as well the Light and Wakefield catchments, River Torrens and other creeks across Adelaide.

Emergency Services Minister Peter Malinuaskas was briefed on the storm at a meeting of Cabinet's Emergency Management Council earlier on Wednesday.

He said the state was prepared for the worst and 165 tonnes of sand had been bagged and distributed.

"I commend South Australians for taking up the offer of sandbags to make sure their homes are in a state of preparedness," he said.

Communities and Social Inclusion Minister Zoe Bettison said the State Government had enacted its Code Blue to ensure there was shelter and food available for rough sleepers during tonight's storm.

"We're also going to have our street-to-home people out so we'll be actively identifying people if they are sleeping rough and letting them know about these increased services," she said.

"Additional accommodation will be available at Baptist Care, they're going to open their Westcare facility, Millers Court just off Wright Street. That's from 5:00pm today."

There will also be additional services for homeless people in Ceduna and on the West Coast.