A wind event associated with a thunderstorm on Tuesday night caused a flare-up on the Prison Fire burning in the Santa Catalina Mountains.
The flare-up was highly visible to people in Tucson.
The flare-up crossed fire lines for a 40-acre gain in the fire's size.
A helicopter is dropping water on the fire.
The fire remains 50 percent contained, but has grown to 280 acres.
A hand crew of 20 firefighters is battling the blaze in rough terrain, assisted by two water tenders, a helicopter and two engines.
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