The National Forest Service says the Prison Fire, burning in the Santa Catalina Mountains, has grown to 240 acres, though firefighters say they have a good hold on it.
The fire was started by a lightning strike at about 6 p.m. Sunday in the Molino Basin drainage.
The fire is at least five percent contained and burning in light fuels which have regrown since the 2003 Aspen Fire.
Two crews of firefighters, a fire engine, two water tenders, and a helicopter have been assigned to fight the fire.
Motorists are advised to avoid the Catalina Highway because heavy engines and water tenders will be traveling on the road.
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