Update: Vista Fire in Riverside County containment now reaches 100%

The creation of this content included the use of AI based on templates created, reviewed and edited by journalists in the newsroom. Read more on our AI policy here.

Updated: 3:05 p.m. April 18

First discovered: 22 hours ago, 4:24 p.m. April 17

Initial location: El Torro Road, North of Lake Elsinore, Riverside County, Calif.

Fire unit: Cal Fire Riverside Unit

Fire type: Wildfire

Fire name: Vista Fire

Vista Fire initially started 4:24 p.m. April 17 on El Torro Road, North of Lake Elsinore in Riverside County, California.

It has burned 183 acres after being active for 22 hours. As of Saturday afternoon, the fire crew successfully encircled the entire perimeter of the fire in control lines. The cause of it is still under investigation.

Fire containment

What does 100% containment mean?

Note that full containment doesn't mean the fire is completely out. In this case, it means that firefighters have managed to get a line completely around the wildfire's perimeter and it is now stopped from spreading. A fully contained wildfire may continue to burn within the containment perimeter but is not likely to spread.

However, there's a significant difference between containing and controlling a wildfire. After the fire is fully contained, the next step is to control it. Controlling a fire means ensuring that the fire can't spread or cross the containment line.

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

United Robots Sacramento

This story was originally published April 18, 2026 at 6:02 AM.