Update: Nearly fully contained - Helios Fire in San Luis Obispo County now at 90%

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Updated: 6:07 a.m. April 20

First discovered: 9 hours ago, 8:43 p.m. April 19

Initial location: Cloverdale Trail and Cactus Trail Valley, San Luis Obispo County, Calif.

Fire unit: Cal Fire San Luis Obispo Unit

Fire type: Wildfire

Fire name: Helios Fire

Helios Fire initially started 8:43 p.m. April 19 in Cloverdale Trail and Cactus Trail Valley in San Luis Obispo County, California.

It has burned 38 acres after being active for nine hours. As of Monday morning, a crew of two firefighters effectively contained 90% of the fire. The cause of it remains under investigation.

Among other resources, an engine has also been assigned to fight the wildfire. According to Cal Fire, "Numerous firefighting air tankers from throughout the State are flying fire suppression missions as conditions allow."

Fire containment

What does it mean for a fire to be 90% contained?

The percentage indicates how much of the fire perimeter has been surrounded by a control line. In this case, it means that 90% of the wildfire is halted from spreading, while 10% 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 April 20, 2026 at 6:32 AM.