Historical
Cyclones are powerful, rotating storms that form over warm tropical and subtropical oceans and generally move from East to West before turning towards higher latitudes. These cyclones are known as Hurricanes in the Atlantic and Northeast Pacific basins, and as Typhoons in the Northwest Pacific basin. Cyclones pose a significant threat upon landfall, causing heavy rain, strong winds, flooding, and widespread damage, which can degrade water quality, spread disease, and destroy infrastructure. In addition to the immediate physical destruction, the aftermath often leads to long-term challenges, such as disruption of essential services, economic loss, and environmental degradation. To mitigate these impacts and support recovery, building broad resilience is essential.
This page presents observed Tropical Cyclones from the International Best Track Archive for Climate Stewardship (IBTrACS) but primarily relies on simulated Tropical Cyclones generated by the Columbia HAZard Model (CHAZ, Lee et al. 2018) for most of the analysis. In most tropical places the occurrence of Tropical Cyclones in any one place is still rare, therefore the historical record is generally too short to allow for a robust estimation of recurrence intervals of these storms. Such historical uncertainty can be reduced somewhat using models, where large ensembles of Tropical Cyclones can be generated. The CHAZ Model simulates tropical cyclones across the oceans and their impact on landfall by generating an extensive synthetic catalog of possible cyclone tracks, offering a more comprehensive view than what can be obtained from observational data alone. The results presented here are currently based solely on the CHAZ Model, albeit driven by a broad array of 12 different Global Circulation Models (from the CMIP6 ensemble). CCKP is offering these products as first examples that are designed to assist users in engaging with Tropical Cyclone data, forming a better understanding of their statistical properties today, and then working in a scenario context to consider possible changes in the future.
CCKP is grateful for the expertise and guidance of the CHAZ Model Team at Columbia University.
We classify Tropical Cyclones using the Saffir-Simpson Hurricane Scale, which uses maximum sustained wind speed.
- Tropical Storm: 34 to <64 knots (63 to <118.5 km/h)
- Category 1: 64 to <83 knots (118.5 to <154 km/h)
- Category 2: 83 to <96 knots (154 to <178 km/h)
- Category 3: 96 to <113 knots (178 to <209 km/h)
- Category 4: 113 to <137 knots (209 to <254 km/h)
- Category 5: >= 137 knots (>=254km/h)
Below, cyclone information is presented as storm tracks and probabilities (number of storms per year), along with aggregated data at the global average, per ocean basin, per Exclusive Economic Zone (EEZ), and by landfall for associated territories or countries.
Section I – Historical Tropical Cyclones Activity Maps and Statistics
The map below displays individual observed storm tracks on the left, with colors indicating their intensity. Given that reliable observational data is only available since 1980, we also provide simulated historical cyclone data on the right, categorized by storm type, to address these gaps.
Users can adjust the visualization range from 0 to 1.5 (representing frequent events, occurring once every 8 months with a probability of 1.5), 0-0.1 (rare events, occurring once every 10 years with a probability of 0.1), and 0.01 (extremely rare events, occurring once every 100 years with a probability of 0.01).
When clicking on any Exclusive Economic Zone (EEZ), the EEZ and its corresponding territory or country are highlighted. The tooltip provides information on the EEZ's cyclone probability and return period, as well as information on landfall. Additionally, plots below are dynamically adjusted to reflect the selected EEZ, the corresponding ocean basin, and the associated landfall territory.
In the charts below, we compare the simulated percentages and counts of various cyclone categories at the global level, ocean basin level, Exclusive Economic Zone (EEZ), and country or territory level associated with that EEZ, which reflects the number of landfalls.
By default, the data is presented at the ocean basin level and for the primary EEZ linked to the selected country. However, users can choose other EEZs from the same country, as well as select additional EEZs from the map above. Since some EEZs span multiple basins, we initially show the primary ocean basin, but users can select additional basins that intersect with that EEZ as needed. Selecting EEZs outside the tropical cyclone range may yield limited or insignificant results, as tropical cyclones rarely reach these areas. This includes EEZs in regions such as the Mediterranean Basin, Arctic Basin, and others outside the typical cyclone zones.
Section II – Basin Timeseries and Seasonal Cycle
Below is the simulated historical annual time series and average seasonality for three categories of tropical cyclones: tropical storms, minor cyclones (Category 1 and Category 2), and major cyclones (Category 3 and above) at the ocean basin level. You can select the desired ocean basin for analysis. Note that the Western Pacific basin excludes the South China and Eastern Archipelagic Seas, which are treated as a separate basin.
The annual time series (displayed on the left) highlights interannual natural variability, a key factor in storm formation that leads to significant year-to-year fluctuations. For instance, El Niño events often increase tropical cyclone formation in the Eastern Pacific but suppress activity in the North Atlantic, Northwest Pacific, and Australian regions. However, it is important to note that interannual variability is less pronounced here due to the use of a multi-model ensemble.
On the right, you can view the daily averaged cyclone activity. Cyclone seasons typically peak in late summer when ocean temperatures are at their warmest, providing the necessary heat and moisture to sustain cyclone development. Low wind shear—minimal variations in wind speed or direction with height—is also critical for cyclone formation and maintenance.