A person has died and an unknown number of homes have been destroyed in fires burning throughout South Australia.
Up to 70 fires have broken out throughout South Australia on a day of catastrophic conditions, threatening townships and homes and forcing residents to seek shelter.
Hundreds of firefighters and several water bombers have been called in to fight the ongoing fire near Cudlee Creek.
It comes amid a deepening bushfire crisis in New South Wales, where two volunteer firefighters lost their lives while travelling to battle blazes in conditions described as "the worst imaginable".
The CFS has declared an emergency warning for the Adelaide Hills fire, east of Adelaide.
It said the Cudlee Creek fire had so far burned about 300 hectares and winds were starting to move towards the west on the fireground.
It said the blaze was moving in a south-easterly direction towards Woodside, Charleston and Inverbrackie, but conditions are continually changing.
A fire is also burning out of control at Maitland, 160 kilometres west of Adelaide, sparking another emergency warning.
The CFS said a series of lightning strikes hit the region a short time ago, around 5 kilometres from the Maitland township.
The fire is now threatening the town.
CFS chief officer Mark Jones said between 8:00am and 12:00pm it had received calls to 28 significant fires.
"Approximately 500 firefighters are in the field firefighting at this time," he said.
"The Cudlee Creek fire is burning in terrain which is particularly difficult to firefight, and under the current conditions is unlikely to be controlled rapidly."
The fire jumped Fox Creek Road and embers are falling on those townships, which are under threat.
There are reports of wineries being impacted by the fire.
A giant water bomber from New South Wales is currently assisting and the CFS has urged people in the area to activate their bushfire survival plans.
"There are roads closed in the area, do not travel unless absolutely necessary," the CFS said.
A fire burning in Adelaide's north has been contained and downgraded to a watch and act for residents in Hillier, Hillier Park, Munno Para Downs, Kudla, Munno Para West and Angle Vale near Gawler.
The fast-moving blaze had been burning in a south-easterly direction towards populated suburbs in Adelaide's north and was deemed an immediate threat to lives and homes.
"The Angle Vale fire is a grass fire moving quickly and early reports are properties may have been impacted," Mr Jones said.
A fire in a storage yard at Old Reynella in Adelaide's south has also prompted a warning to residents from the Metropolitan Fire Service.
The incident is causing smoke to drift across the area and people with respiratory issues have been advised to stay inside and close their doors and windows.
Power cut to thousands of customers
SA Power Networks has cut power to more than 2,000 customers at the bushfire zones.
Suburbs affected in the Adelaide Hills include Lobethal and an area north of Woodside.
Power is also out around Cudlee Creek.
In Adelaide's northern suburbs, power has been cut to Roseworthy and may be cut to Two Wells, Virginia and Edinburgh.
"Due to the rapid escalation of weather and fire conditions we may disconnect power," SA Power Networks said.
In total, there are almost 12,500 customers across the state without electricity with temperatures in the low to mid 40s in some parts.
Martin, who lives on Cudlee Creek Road, told ABC Radio Adelaide his family has evacuated the area.
"My property is halfway between Cudlee Creek and Lobethal," he said.
"Looking across in a westerly direction towards Lenswood … I'd say the flames would be well in excess of 80 to 100 feet [high].
"I just thought I'd stop … unbelievable scenes, just to take this in really because the flames are absolutely mammoth, and the conditions are just unbelievably bad.
"The wife has taken our two boys and the dogs down to the city, I've turned my cattle out into a rather large paddock and opened a few extra gates and they've got access to a very large dam.
"It bothers me when I see people staying, at the end of the day it's only a house."
Cool change on its way amid heatwave
Much of the state is facing catastrophic fire conditions as it swelters through its fourth day of a heatwave.
Adelaide is forecast to reach a top of 46 degrees Celsius after having its hottest night on record at the West Terrace weather station.
Parts of the state are tipped to reach close to 50C before a cool change is expected this afternoon.
Temperatures have again soared into the mid to high 40s, with Keith reaching 49.2C.
A severe thunderstorm warning has been issued for a large part of the state, including the bushfire affected areas.
Thunderstorms are developing and are likely to produce damaging wind gusts in excess of 90 kilometres per hour during the afternoon.
Bureau of Meteorology senior meteorologist Vince Rowlands said the cool change was expected to reach Adelaide about 4:00pm.
"At this stage probably thinking around 3:00pm [it] should be around the foot of the Fleurieu [and] Yorke peninsulas, sort of just past Wudinna, extending up into the north-west pastoral.
"Probably expecting it to come through Adelaide initially with a bit of a waffly wind change, not expecting that to cool down temperatures too much, maybe about 4:00pm.
"Then we start to see a more significant southerly come through somewhere between 5 and 6:00pm.
"That will then bring substantial change in temperature."
Residents north of Adelaide 'not prepared'
Earlier, TJ who lives in Blakeview, a suburb in Adelaide's north, said the emergency warnings for the area were worrying as many suburban residents were not prepared.
"Where I am, we've already got some emergency warnings dipping into our area," he told ABC Radio Adelaide.
"We live in a properly suburban suburb, none of us have bushfire plans.
"Munno Para Downs is where the fire is and it's burning towards us, once it clears Munno Para West we might have to look to evacuate and no-one's got plans to do that.
"There's a lot of elderly people in here who are probably not sure what to do.
"We are evacuating now to be safe because it's burning in our direction so, you never expect to have to do that in a metropolitan suburb.
"People don't make bushfire plans in this area."