A grass fire is burning on both sides of Highway 99 near Keyes Road, impacting traffic and closing some lanes and on-ramps. The fire is affecting southbound Highway 99 traffic, according to the CHP. Traffic is slowing more than a mile away from the fire, near Mitchell Road in Ceres. A fire truck is currently blocking the slow lane as it fights the blaze, which began at roughly 3:15 p.m. According to the CHP, Keyes Road is closed over Highway 99. The Keyes Road on-ramp to southbound Highway 99 is also closed. A second grass fire was also sparked near the Taylor Road exit on Wednesday afternoon, but was quickly extinguished.