When a 7.3-magnitude earthquake rumbled beneath the Bering Sea on Wednesday 50 miles south of Sand Point, Alaska, authorities sent their first tsunami warnings directly to the nearest public radio station, KUCB in the Aleutian Islands town of Unalaska. Along with other local NPR and PBS stations, it immediately broadcast alerts for residents and tourists to get to higher ground. By the time the Alaska Emergency Management Agency contacted Sand Point and other island communities, the word was already out, said the agency’s director, Bryan Fisher.