A almost decade-long drought combined with record high temperatures have created tinder-dry conditions, and it is thought some of the fires may have been started deliberately. Some 6,000 residents fled the city.
Of the 99 fires in the country, 64 ones are being fought, 30 ones are controlled and five are extinguished, and due to the advance of the fires, a constitutional exception area and a state of catastrophe zone has been declared in the Biobio Region, said the media.
Wildfires have continued to wreak destruction in central and southern Chile.
Four wildland firefighters and and one air tanker pilot have been killed battling the fires since December 28.
"This is an extremely serious situation - of horror, a nightmare without an end", the mayor of the coastal city of Constitucion told the German broadcaster.
But those efforts are often undone as winds or smouldering ash spread the fires again.
Chile's Conaf forestry service said that 35 of the fires were still out of control.
The fires have struck mainly in sparsely populated rural areas in the central regions of O'Higgins and El Maule, where the fourth victim died on Wednesday.
People embrace in front of buned homes in Santa Olga after a wildfire ravaged wide swaths Chile's central-south regions, January 26, 2017.
"Chile is living the greatest forest disaster in our history", Bachelet said.
The U.S. Embassy in Santiago said earlier this week that the U.S. government was donating $100,000 "for the local procurement and delivery of firefighting equipment, such as chainsaws and weather monitoring tools requested by the National Forestry Corporation". And on Thursday, Bachelet announced her country was accepting more Russian tanker planes and helicopters. Russian Federation already sent a super-tanker aircraft capable of dumping tons of water on fire to Chile to combat the flames. It is being deployed near the town of Hualane in the Maule region. Chile's interior ministry said the country could expect hotter temperatures and stronger winds in the coming days, which would fan the flames even further.