A brush that broke out Tuesday on the west end of Jurupa Valley scorched roughly an acre in the Santa Ana River bottom before crews deployed to the location.
The non-injury blaze was reported at 3:45 p.m. in the area of Etiwanda Avenue and 66th Street, just east of Interstate 15, according to the Riverside County Fire Department.
The agency said multiple engine and hand crews from the county, as well as the city of Riverside Fire Department, encountered flames moving at a slow to moderate rate in heavy brush.
Despite breezy conditions, as of 4:30 p.m., the blaze had largely stalled, confined to a tree line between Arlington Avenue in Riverside to the east and the Goose Creek Golf Club to the west, according to reports from the scene.
A Cal Fire water-dropping helicopter was summoned to make drops on the brusher.
No homes or other structures were immediately threatened, and no evacuation orders appeared imminent.
Firefighters were making progress encircling the blaze, which may have started in a homeless encampment, officials said.
Cooking, warming and debris fires are common due to transient activity in the river bottom throughout the year.