

This map shows the paths of every hurricane and cyclone detected since 1842. Nearly 12,000 tropical cyclones have been tracked and recorded, and the National Oceanic and Atmospheric Administration keeps them all in a single database. Long-term datasets can be really interesting and scientifically valuable, and this one is undoubtedly both.

In the image above, you can clearly see that more storm tracks have overlapped in the western Pacific ocean and northern Indian ocean. This is largely because of the length of the typhoon season, which basically never stops in the warmer waters there.

The tracks of the earliest storms are based on mariner's logs and storm records, collected from various countries, agencies and other sources. Reconciling data from these different entities was tough. Most international agencies had their own set of codes for cyclone intensity, and only recorded this information once per day. India was even using different wind thresholds to designate cyclone stages.

Somehow, NOAA's National Climatic Data Center managed to wrangle all these various reports. Originally, at the dawn of the mainframe computer age, much of this data was stored in the form of decks of punch cards, sometimes with just one position and intensity measurement for one storm recorded on each card. Later systems used 80-column cards to boost this to four measurements per card. A similar tracking system is still in use today, of course without the physical cards.

Many storms were surely missed in the early days of tracking. But since the advent of geostationary satellites, and in particular NOAA's GOES series of weather-tracking satellites which was first launched in 2001, the data has gotten better and more complete. The entire globe gets a look every few minutes, and no storm goes unreported.

All of this data, nearly 170 years' worth, is kept by NOAA in a single database called IBTrACS, and as a result, we have these beautiful maps from the NOAA Environmental Visualization Laboratory (and a whole bunch of science and other maps and stuff). The data is freely available to anyone.

The map above of hurricane frequency shows that the entire Western Hemisphere seems to have an easier time than the Eastern Hemisphere. But the story looks different in the image below, which shows storm intensity based on each storm's maximum sustained windspeed. In this image, things don't look so great for the Western half of the globe, with a much bigger swath of stronger storms in the Northwestern Atlantic ocean. The Eastern hemisphere shows the highest concentration of intensity near the Philippines.



Read more on the history of NOAA's hurricane tracking database.