Here's the Park's advice if you should meet a black bear:
"Never approach a bear. Keep children beside you. There is more safety in numbers; it is best to travel in a close group. If a bear approaches you, stand up tall, and make loud noises: shout, clap hands, clang pots and pans. When done immediately, these actions have been successful in scaring them away. However, if attacked, fight back! Never try and retrieve anything once a bear has it. Report all incidents to a park ranger."
In recent drought years, bears have discovered "dumpster buffets" in populated areas. The Park asks your cooperation in bear control:
"In campgrounds and picnic areas, if there is a food storage locker provided, use it. Avoid storing food and coolers in your vehicle. If you must, store food in airtight containers in the trunk or out of sight. Close vehicle windows completely. Do not store food in tents or pop-up campers in campgrounds, or in vehicles at trailheads. Food, coolers, and dirty cookware left unattended, even for a short time, are subject to confiscation by park rangers; citations may be issued. Dispose of garbage in bear-resistant dumpsters and trash cans. Human-fed bears usually end up as chronic problems and need to be removed - "A fed bear is a dead bear." In the backcountry, store food, scented items, and garbage in commercially available bear-resistant portable canisters, or carefully hang food 10 feet up and 4 feet out from a tree. Pack out all garbage. Never try to retrieve anything from a bear. Report all bear incidents to a park ranger. Do not leave pets or pet food outside and unattended, especially at dawn and dusk. Pets can attract animals into developed areas. Avoid walking alone. Watch children closely and never let them run ahead or lag behind on the trail. Talk to children about lions and bears and teach them what to do if they meet one."