Authorities say 11 properties have been damaged in a bushfire on South Australia's Lower Yorke Peninsula that was caused by a "power network fault" just outside of Yorketown.

Key points: The bushfire on South Australia's Lower Yorke Peninsula has been contained

The bushfire on South Australia's Lower Yorke Peninsula has been contained At least 11 properties have been affected by the fire and 5,000 hectares burned

At least 11 properties have been affected by the fire and 5,000 hectares burned A "power network fault" has been blamed for starting the fire

The fire started during Wednesday's catastrophic fire conditions and broke through containment lines early this morning, but has since been downgraded to an "advice" message.

There were 69 fires across South Australia yesterday as the state sweltered through temperatures above 40 degrees Celsius alongside strong winds.

About 5,000 hectares of land was burnt around Yorketown, compared with 85,000 in the 2015 Pinery fire.

Firefighters say the driver was rescued before the fire approached. ( ABC News: Claire Campbell )

There were 33 people who were treated for minor fire-related injuries, including four taken by ambulance to hospital.

The Country Fire Service (CFS) said the fire was contained late Thursday afternoon.

CFS assistant chief officer Brenton Eden said the fire was now "very benign" and its area was not expanding.

Yorketown incident controller Richard de Groot said "an electrical infrastructure issue adjacent to town" was to blame for the fire.

"I'm pleased to say it's not arson," Mr de Groot said.

"It is a result of a power network fault."

SA Police and CFS fire cause investigators have focused on a burnt-out transformer near the Yorketown water tower, however Mr de Groot would not name this location as the place the fire started.

Fire cause investigators look at a burnt-out transformer near Yorketown. ( ABC Radio Adelaide: Malcolm Sutton )

Mr de Groot thanked the public for their "diligence and cooperation".

"We're very appreciative of the community support we've had, along with the support from emergency services," he said.

"But of course, we'd like to focus and sympathise with the communities that have been impacted on, and I can ensure you that all the emergency services and a very great amount of goodwill from the community will help them get through this period."

Families affected by the Yorketown fire can apply for grants of up to $700 from the State Government.

Two men give water to a lamb they rescued near Edithburgh. ( ABC Radio Adelaide: Malcolm Sutton )

Some farmers have 'lost everything'

Yorketown resident Gina Voigt said her property was scorched in the fire, destroying crops and fences.

She said the first sign of trouble was when the power blacked out.

A home destroyed by the Yorketown bushfire in South Australia. ( ABC News )

"Twice the power blacked out, we couldn't use the phone anymore, we thought what's going on?" she said.

"I said 'it's too late, the fire is here'.

"The fire was on the end of our property already … it was all along the left and all along the right, it was just full-on blazing everywhere."

Ms Voigt said the flames were 15 metres high.

"I could see that there [were] houses on fire because of the black, billowing smoke," she said.

"It was just unbelievable, I've never seen anything like this in the whole 23 years I have been here."

She said some of her neighbours had lost their homes.

"They've lost everything, their homes are gutted, absolutely gutted."

Flames travelled close to the Wattle Point wind farm. ( ABC Radio Adelaide: Malcolm Sutton )

At least 11 properties affected

Police Commissioner Grant Stevens said crews were still assessing the damage at the fireground, but he believed there had been 11 properties affected.

"The rapid damage assessment teams are moving into the fireground now to make further assessments in relation to damage, particularly around Edithburgh, and also around Price, which is 45 minutes away from Edithburgh, which was also subject to some loss," Mr Stevens said.

"At this point in time, there are no losses of life identified.

"We had concerns for one elderly gentleman, who has been located safe and sound."

Tony Hoare's property was burnt when the bushfire jumped containment lines, but he said he got off "fairly lightly" compared to others. ( ABC News )

Yorketown property owner Tony Hoare said he had got off "fairly lightly" in comparison to a lot of others.

"My cousin's place, their house is gone. My other cousin they have lost a huge shed and all machinery — it's totally gone," he said.

"Mainly what concerns me is the livestock at the moment.

"I was in the town and I was trying to get out here and couldn't. It was that bad, you couldn't see with smoke and dust so we were sort of stuck there and couldn't go anywhere.

"There wasn't a lot we could do."

The ABC has seen dead livestock at properties impacted by the fire.

Authorities are assessing damage on the Yorke Peninsula. ( ABC News: Claire Campbell )

Edithburgh evacuated as fire reaches edge of town

A safe haven has been set up at the Stansbury Bowling Club for residents affected by the fire and the Red Cross has set up a register service for family, friends and loved ones affected by the fire.

Yorke Peninsula Mayor Darren Braund has evacuated his family from Edithburgh.

"The fire jumped some containment lines and police and emergency vehicles were going around trying to alert as many people as they could to get out of the town," he told ABC Radio Adelaide.

"All of a sudden the whole town just filled with smoke. The visibility was very bad by the time we were leaving."

He said it was hard to know how many people had evacuated.

"I think people are just in a bit of shock reacting to the situation," he said.

"I've been up all night with some people in the Edithburgh Institute who were evacuated there before they had to leave that position and had to go further north to Stansbury."

A tractor alight near Yorketown. ( Facebook: Tom Giles )

About 400 people live in Edithburgh.

"I know there were about 100 people in the caravan park at the same time so it's a bit of an unknown," Mr Braund said.

Adam Pitt, who lives in Stansbury, told ABC Radio Adelaide friends from Edithburgh evacuated to his home.

"Edithburgh has been evacuated and I've just had word from a couple of mates who are taking refuge here for a little bit that the fire has just reached Park Terrace on the edge of Edithburgh," he said.

"A lot of locals at Edithburgh have taken refuge to the manmade water pool and to the jetties.

"There's also 150 people heading towards Stansbury to the bowls club.

Mr Pitt said his friends were concerned their home may have been lost in the fire.

"They are a little bit shaken at the moment as to be expected as Park Terrace is actually past their house," he said.

Livestock have been killed during the fires. ( ABC News: Lincoln Rothall )

Smoke hits Adelaide and east of state

The CFS has issued a warning about the significant smoke from the Yorke Peninsula which had covered the Adelaide metropolitan area.

It has advised residents to close all doors and windows and to stay indoors if the smoke is causing concern, as well as warning people to take care when driving due to reduced visibility.

There are reports the smoke and dust has reached as far as Mannum and Murray Bridge, east of Adelaide.

The South Australian Environmental Protection Authority said air quality across the state was very poor this morning due to the bushfires — the worst since the 2015 Sampson Flat bushfire.

Several other fires on Wednesday reached emergency warning levels — including near Angaston in the Barossa Valley and near Port Wakefield — before being downgraded as a result of firefighting efforts.

Adelaide has been covered in a thick haze of bushfire smoke and dust due to the Yorke Peninsula bushfires. ( ABC News: Nick Harmsen )

Bureau of Meteorology acting supervising meteorologist Paul Lainio said winds across South Australia were now easing and moister than before.

"We are expecting to see continued improvement as a high-pressure cell moves in and those winds further ease during the next 24–36 hours," Mr Lainio said.

He said high temperatures would be back on Monday, accompanied by a northerly wind, but they would be not as bad as on Wednesday.

SA Premier Steven Marshall said seven districts were rated at catastrophic fire danger levels yesterday, the highest in the history of the state.

"I want to express my gratitude to the CFS, the State Emergency Services and everybody who's been working on our response to this very difficult situation," Mr Marshall said.

"I'd also like to express my great sympathy to those people who have suffered loss over the last 24 hours, there has been quite substantial loss affecting land, property, sheds and stock right across the state but particularly at the moment on the Yorke Peninsula."