(UK version sorry no experience in US) Probably let the stations call in to control to let the stations to sort themselves out and let them be on standby for going to police stations, hospitals, prisons, car homes and urgent calls. Let the dispatch supervisor call Boss of fire service. Boss of Fire call Prime Minister office. Get the Prime Minister to declare State Of Emergency to let the Military to help. Liase with police and ambulance. Answer calls as normal but only dispatch to priority calls.