SACRAMENTO (CBS13) – Firefighters are unable to determine the exact cause of a wildland fire that burned dangerously close to Cal Expo on Friday.

Investigators have listed the cause of the fire as undetermined after they were unable to find evidence pointing to the source — human or otherwise, said Sacramento Fire Department spokesman Roberto Padilla.

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The fire started around 2:14 p.m. in an area along the north side of the American River known as Bushy Lake and burned several acres of vegetation south of Cal Expo.

Members of the public and staffers at Cal Expo, including those at the water park, were evacuated because of smoke, and the evening’s Sacramento Republic FC soccer game was canceled.

“The flames were definitely several hundred feet tall. These are oak trees that are well over 100 feet. They just basically became Roman candles,” said Padilla. “This was a very explosive fire. At one point it wasn’t about extinguishing the fire, it was about getting people out if the way.”

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Forty acres burned and nearly 200 firefighters and 40 units were on the scene trying to put out hot spots and contain the blaze.

Approximately 10 vehicles were reportedly scorched by the fire, but no structures were damaged. Two palm trees at Cal Expo were also burned.

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