5 Freeway through Grapevine was placed under a dense fog advisory by the National Weather Service on Wednesday at 5:46 p.m. The NWS Hanford CA states to prepare for, “Visibility one quarter mile or less in dense fog.”“Low visibility could make driving conditions hazardous,” according to the NWS. If driving through fog becomes inevitable, remember these safety guidelines:Moderate your speed:Slow down and allocate extra travel time to reach your destination safely. If available, employ your fog lights. For more local weather alerts, visit our Weather Advisory page