Weather conditions across South Australia on Friday will test all the resources of the state's Country Fire Service as temperatures surge into the low to mid 40s.
Only on Saturday, when the mercury dips to the low 30s in the coastal centres, will the state get any relief from severe conditions.
"Everything is super dry, ready to burn," Mr Watts told the ABC on Wednesday.
"Everything is available to be consumed by fire - tinder dry."
"It's up to the weather gods to help us out and give us some respite," Mr Watts said.
"We might get a bit on Saturday during the day in coastal areas of the state. Then we're back into and no relief in sight until Wednesday or Thursday next week."
Three others were burning in the state's north but were of less concern.
A fire at Sevenhill, in the Clare Valley, continued to burn within control lines and was being monitored.
It has destroyed about 30 hectares of wooded land after being sparked earlier this week.
Police said later they were investigating the St Ives blaze that also destroyed one home causing about $200,000 damage.
A spokesman said the fire started alongside the South Eastern Freeway and was considered suspicious.