South Korea's worst-ever wildfires double in size, killing at least 28 and incinerating temples

Wildfires raging in South Korea doubled in size on Thursday from a day earlier, as authorities called the blazes the country's worst natural fire disaster with at least 28 people killed and historic temples incinerated.

More than 33,000 hectares has been charred or were still burning in the largest of the fires that began in the central Uiseong county, making it the biggest single forest fire in South Korea's history. The previous record was 24,000 hectares in a March 2000 fire.

"We are nationally in a critical situation with numerous casualties because of the unprecedented rapid spread of forest fires," acting President Han Duck-soo told a government response meeting.

South Korea relies on helicopters to fight forest fires because of its mountainous terrain, and the military has released stocks of aviation fuel to help keep them flying as they try to douse flames across mountainous regions in the southeast of the country that have been burning for nearly a week.

More than 120 helicopters have been deployed in three regions battling the blazes, the safety ministry said.

The fatalities include a pilot whose helicopter crashed during efforts to contain a fire Wednesday and four firefighters and other workers who died earlier after being trapped by fast-moving flames. 

Authorities haven't disclosed details of the civilian dead, except that they are mostly in their 60s or older who found it difficult to escape quickly or people not willing or able to heed evacuation orders.

The Uiseong fire began spreading quickly on Wednesday, reaching the coastal county of Yeongdeok 51 kilometres away in just 12 hours, said Won Myung-soo, director of satellite imagery analysis for the national forestry service.

The wildfires have been moving east rapidly, spreading almost to the coast, aided by gusty winds and dry conditions.

Some rain, but not much

On Thursday evening, it rained briefly in some parts of the affected region. Precipitation of around one millimetre was too little to extinguish the main fire, but will help contain it, officials said.

About the same amount of rain is expected for some areas on Friday.

The wildfires have carved a trail of devastation through an area equivalent to about half the area of Singapore, ravaging everything in their path including historic temples and homes in the mountainous forest regions of North Gyeongsang province.

Teams of firefighters are on standby to protect the UNESCO World Heritage sites of Hahoe Village and the Byeongsan Confucian Academy in the city of Andong, if a blaze jumps the stream that flows around them.

The picturesque folk village has traditional Korean houses, many with thatched roofs, while the Confucian academy dates back more than 450 years.

The fires have already badly damaged other historic sites, including much of Gounsa Temple in Uiseong, which was built in 681.

"The buildings and remains of what Buddhist monks have left over 1,300 years are now all gone," said Deungwoon, the head of the Gounsa Temple.

Experts have said the Uiseong fire showed extremely unusual spread in terms of its scale and speed, and that climate change is expected to make wildfires more frequent and deadly globally.

Higher temperatures amplified by human-caused climate change contributed to the existing seasonally dry conditions, "turning dry landscapes into dangerous fire fuel" in the region, the Climate Central group, an independent body made up of scientists and researchers, said in a report.