Update: Hayden Fire grows to 40 acres in Merced County, now 50% contained

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Updated: 3:24 p.m. July 7

First discovered: 2:11 p.m. July 7

Initial location: HWY 140 East, Planada, Merced County, Calif.

Fire unit: Cal Fire Madera-Mariposa-Merced

Fire type: Wildfire

Fire name: Hayden Fire

Hayden Fire initially started today at 2:11 p.m. on HWY 140 East, Planada in Merced County, California.

As of Tuesday afternoon, it had burned 40 acres, an increase of 20 acres since the last update. By Tuesday afternoon, 50% of this fire was brought under containment. At this time, details about the cause of the fire are unknown.

Fire containment

What does it mean for a fire to be 50% contained?

The percentage indicates how much of the fire perimeter has been surrounded by a control line. In this case, it means that 50% of the wildfire is contained from spreading, while 50% is still uncontrolled.

Containment is part of a larger plan for managing a wildfire. It is normally expressed as a percentage and it refers to how much of the fire perimeter has been surrounded/enclosed by a control line that firefighters create. The containment percentage indicates a certain level of control, but it doesn't always correlate to safety level. Also, it's important to note that containment doesn't mean a fire is out.

How is containment measured?

The incident's central command constantly receives progress reports from firefighters on the ground. As the fireline is constructed, inspected or reinforced, mappers record those details to adjust the containment percentage. The percentage tells the public how much of the fire perimeter is believed to not go beyond the control lines.

Source: Cal Fire

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This story was originally published July 7, 2026 at 2:51 PM.