Emergency warnings remain in place for the towns of Parndana and Vivonne Bay while Kingscote is also at risk after a second major escalation of the Kangaroo Island bushfire.
A watch and act warning was issued for the outskirts of Kingscote, the island's largest town, late on Thursday.
It was the first time warnings had extended so far east since the bushfires began in late December.
Serious fears were held for Parndana as a fire front moved through the central districts, while there were some reports that a fire front bearing down on Vivonne Bay had been halted.
However, the emergency warning extended across an area to the east, west and north of the small south coast village.
A cool change was approaching from the west late on Thursday, bringing some rain but unlikely enough to significantly impact areas burning strongly.
However, cooler and more humid conditions are likely to give firefighters a chance to strengthen containment lines.
Despite the watch and act warning for the western outskirts of the town, which also extended to American River further to the east, authorities said Kingscote was not considered at immediate risk.
"We're quite comfortable that if anything does come up we can deal with that because it is a safer place," deputy incident controller Ray Jackson said.
Nevertheless, CFS chief officer Mark Jones warned against complacency.
"The condition of the fire is such that it's unlikely that they will be extinguished by the rain, and they will continue to burn," Mr Jones said.
"These fires are travelling quickly.
"What might have seemed safe this morning may not be safe by evening so we want people to get the message and to move away from the fire areas."
As the fire roared towards Parndana, store owners Jen and Mike Boyd elected to stay but were fearful of what was heading their way.
"I'm scared it's going to go and it's everything we have in the world," Mrs Boyd told AAP.
"It has our house next to it, so if it goes up we lose our income and our home."
"I'm also scared for the town."
Other residents who left Parndana placed sprinklers on the roofs of their homes, hoping they would prevent them burning down.
Army personnel had gone from door to door, urging people to leave.
At the peak of the emergency last week, Parndana also came under threat with locals saying the glow in the sky was "just incredible".
The fire has already destroyed 160,000 hectares across Kangaroo Island including most of the famed Flinders Chase National Park.
It has claimed two lives with outback pilot Dick Lang, 78, and his 43-year-old son Clayton killed as they returned to their home.
The blaze first broke out on December 20 from a lightning strike but escalated rapidly last Friday before jumping containment lines again on Thursday.
Australian Associated Press