Drones might soon deliver a heads-up when natural disasters are about to strike. Researchers have developed a communication system that uses a drone network to provide early warnings for disasters. The challenge wasn't so much the drone-to-drone communication as the battery life. Where a typical hobbyist drone rarely lasts more than half an hour in the air, a smarter resource allocation method helps this system lasts three to five longer while covering a large area. The drones can also form a WiFi hotspot that keeps people online when conventional infrastructure has fallen apart.