Firefighters conducted overnight operations, Sunday, to put out a wildfire that has burned more than 100 hectares, the equivalent to 140 times the size of a football field, in the eastern city of Samcheok, Gangwon Province.
Korea Forest Service (KFS) said 340 officers will be mobilized to continue efforts to put out the fire that broke out Saturday.
After sundown, 26 firefighting helicopters and 3,200 officers returned home due to poor visibility at night. At least 15 firefighting helicopters and 1,500 officers resumed operations to put out fire at sunrise Sunday.
The cause of the fire remains unclear, authorities said.
"Dispatching officers on the ground is difficult as the mountainous area is very steep and highly dangerous for them to conduct operations on," a KFS official said.
"Water from the helicopters is feared to scatter in the air, not touching the ground. Extremely dry air and strong wind is also exacerbating the situation," he added.
When a wind blows at the speed of 6 meters per second, a fire spreads up to 15 meters farther within a minute compared to no wind.
"We believe the fire could have traveled up to 26 times faster on the back of the wind," he added.
Firefighters are also trying put out a fire in a mountainous area near Gangneung. They have extinguished a fire in Sangju, North Gyeongsang Province. The fires in these two locations broke out Saturday.
The Gangneung fire was initially thought to be contained Sunday night after destroying 33 private houses and 50 hectares of forest, but it reignited, the authorities said. More than 310 residents were ordered to evacuate their homes.
The fire started on a hill near Daegwallyeong, a major mountain pass on the Taebaek Mountain range, around 3:30 p.m. Saturday.
Meanwhile, the fire in Sangju started at 2:13 p.m. Saturday and was extinguished after about 20 hours.
According to the Sangju city government and the forest authority, the fire was put out on Sunday after damaging 13 hectares of forest.
One mountain climber was killed and two others were injured due to the blaze and taken to a nearby hospital.
Authorities said 215 nearby residents were ordered to evacuate.
According to data compiled by the Gangwon Province over three years, an average of 808 fires break out every year.
Almost two-thirds, or 65.4 percent, were caused by careless activities by mountain climbers.
Cigarette butts not completely put out accounted for the most (36 percent), followed by burning trash (21 percent).
A fire on March 9 in Okkye, Gangneung, that destroyed 75 hectares was caused by cigarette butts thrown away by two smokers.
Authorities advised against bringing lighters or other equipment for cooking, saying precaution is always the best option to countermeasures after the fact.
Under the law, arson is a criminal offense punishable by seven years in prison. An individual who set a fire without premeditation is also subject to a prison term of up to three years or a 15 million won ($13,000) fine.