Aided by cooler temperatures and higher humidity, crews fighting the Rocky fire achieved 50 percent containment Friday, with 69,600 acres consumed.
Highways 20 and 16 reopened Friday at 10 a.m., according to the California Department of Transportation.
A closure of the two highways had been in effect since Aug. 1, when the Rocky fire expanded to 27,000 acres. With containment reported at 45 percent early Friday morning, those highways were cleared for traffic.
Evacuation orders and road closures in the Spring Valley area also were lifted Friday morning, allowing about 800 residents to return to their homes, according to Daniel Berlant, a spokesman for the California Department of Forestry and Fire Protection.
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Overnight and throughout the day, the affected acreage remained constant as containment steadily climbed. If the weather continues to cooperate, Berlant said full containment is expected next week.
Thunderstorms raging through the Sierra and northern San Joaquin Valley overnight Thursday narrowly missed the Rocky fire region, according to the National Weather Service. Lightning in the areas affected by the Rocky fire could have increased the chances of new blazes, forecasters said.
Bee staff writer Cathy Locke contributed to this report.