A vegetation fire in the Santa Maria Riverbed sent up a large column of smoke Tuesday afternoon.

Personnel from the Santa Maria Fire Department and Cal Fire in San Luis Obispo County were dispatched to the incident in the riverbed north of city limits.

The fire burned grass and brush, but moved slowly on the east side of the Santa Maria Riverbed, according to Cal Fire representatives.

Crews stopped the forward progress of the fire at approximately 3:45 p.m., estimating it had blackened 4 acres. 

The cause of the fire remained under investigation.