Storm Archive

The problem

An archive, not a feed — and the archive changes

The whole record of Atlantic hurricanes is one public text file from the National Hurricane Center. Reading it is easy; reading it correctly is not. The file is revised as old seasons are reanalyzed, a storm’s strongest wind is not always its category, and the early decades are missing names and pressures.

Watch it work

Episode 9 — Storm Archive (5:46)

One public source end to end: where the hurricane archive lives, the three details that cost the most time, and the map and globe it turns into.

What it covers

One source, three details, one map

• The source: HURDAT2, the best-track record kept by the National Hurricane Center at NOAA — one comma-separated text file of about seven megabytes with every Atlantic storm from 1851 to the last season. Each storm has a header line, then one line every six hours with its position, status, wind and pressure; extra lines mark events such as landfall. The file name carries the revision date: the one in Storm Archive was revised on September 12, 2026, and from 1900 on it holds 1,617 storms and 46,296 positions.
• Detail one, history gets revised: compared with the revision that ended at the 2024 season, this one removes sixteen systems from 1971 to 1975, lowers Hurricane Edith of 1971 from Category 5 to Category 4, and adds the 2025 season — thirteen storms, including three Category 5 hurricanes, Erin, Humberto and Melissa. Storm Archive records which revision it uses, and its About box shows the file name and date.
• Detail two, the peak wind is not the category: storms keep blowing after they stop being tropical, and the file marks those stages as extratropical. Dexter in 2025 reached seventy knots only after it had become extratropical, so it was never classed as a hurricane. Taking the peak wind at face value mislabels 22 storms since 1900, so Storm Archive takes the category from the tropical stages only and draws the rest in gray.
• Detail three, the early records are thin: every storm before 1950 is unnamed, 269 of the 435 storms from 1900 to 1949 have no pressure reading at all, and winds are recorded in five-knot steps. Fewer storms in an early year does not mean fewer storms happened.
• How it becomes a map: the panel filters the archive by years, by minimum intensity and by name; every track is drawn thin and faint in its Saffir-Simpson colors, so the busiest paths build up where storms travel most; selecting a storm redraws it in full color with a card for peak wind, pressure, lifespan and a wind chart; a Hall of Fame lists the 44 Category 5 hurricanes since 1900; and a 3D globe lifts the selected storm into a ribbon whose height follows its wind.

What it does not do

• Not a forecast — Storm Archive is an archive; for storms happening now, use the National Hurricane Center.
• Not every basin — it maps the Atlantic basin from 1900, not the Pacific or the years before 1900.
• Not a live copy of the file — it shows the revision named in its About box until the next rebuild.

Where the data comes from

Every source in the episode

• NHC data archive, HURDAT2 — nhc.noaa.gov/data/#hurdat
• HURDAT2 Atlantic file, revised 2026-09-12 — nhc.noaa.gov/data/hurdat/hurdat2-1851-2025-091226.txt
• HURDAT2 format description — nhc.noaa.gov/data/hurdat/hurdat2-format-atl-1851-2021.pdf
• NWS disclaimer (public domain) — weather.gov/disclaimer
• Source sheet with every endpoint — allthingsspatial.io/pages/sources.html

The track data is published by the NOAA National Hurricane Center as HURDAT2 and is in the public domain unless noted. The credit sits in the Storm Archive footer and its About dialog.