Why can the same storm have two completely different names?

A single typhoon crossing the Philippines can carry two completely different names at once. The Japan Meteorological Agency gives western Pacific storms their official international names once they become tropical storms, but the Philippines' own weather agency, PAGASA, also names systems that form or become tropical depressions inside its self-defined area of responsibility. The result is that storms in the region often have two names: one used by the international press, another on Philippine broadcasts.

Naming storms after people is actually a relatively recent habit. Before it caught on, cyclones were named after the places they hit, objects, or the saints' feast days on which they struck. Credit for naming storms after people in the first place usually goes to Clement Wragge, a government meteorologist in Queensland, Australia, who gave personal names to weather systems from 1887 to 1907. When he retired, the practice died out almost entirely — it wasn't revived until the final years of World War II, in the western Pacific.

Today, eleven official warning centers around the world name tropical cyclones, and a storm keeps its name for its entire lifetime specifically so forecasters and the public can track it without confusion, especially when several storms are active at once. In the North Atlantic, the US National Hurricane Center draws from six rotating alphabetical lists that skip the letters Q, U, X, Y, and Z and alternate between male and female names from storm to storm.

A name isn't permanent, though. Any member of the relevant World Meteorological Organization committee can request that a name be retired after a storm causes outsized death or damage — the Philippines sets a specific bar of at least ₱1 billion in damage or 300 deaths. Oddly, a proposed replacement name can be rejected too, for reasons as practical as how well it fits into a tweet. Papua New Guinea skips the debate entirely: its storm names are automatically retired after a single use, no matter how much damage was done — while in Japan's own domestic press, typhoons usually aren't referred to by name at all, just by number.