Disaster Classification System

Historical and Current Classification System of Disasters

A Brief History of the EM-DAT Classification System

EM-DAT’s classification system originally started with a simple 20-type list1. However, in 1992, CRED and other international stakeholders proposed a hierarchical classification system2 that distinguishes natural and man-made disasters (described as technological disasters in EM-DAT). A further distinction was based on the timing of disasters: slow vs. rapid onset disasters.

In the 2000s, CRED collaborated with Munich Re and other stakeholders on a common classification system3. Since then, EM-DAT’s main classification system has followed the logic of referring to the hazard or event triggering the disaster. Consequently, some disasters were reclassified, and some types were removed from the primary classification system. This was the case for famines reclassified as drought for the most part4. However, “famine” offers more information than “drought.” Therefore, in order not to lose this added value, EM-DAT has adopted the secondary classification system of Associated Disasters. This describes disasters that coincide with or result from the primary type.

In 2014, the Integrated Research on Disaster Risk (IRDR) working group, which included CRED, established a new reference called the Peril Classification and Hazard Glossary. This document is currently the primary reference for classifying natural hazards in EM-DAT, which divides them into six main groups: Geophysical, Hydrological, Meteorological, Climatological, Biological, and Extra-terrestrial. EM-DAT also includes more detailed subtypes.

Natural Hazards Subgroups and Types in the IRDR Peril Classification and Hazard Glossary

Main Classification Tree

The main classification tree has four levels of depth, so disasters are divided into groups, subgroups, types, and subtypes, as presented in the EM-DAT Public Table columns. The three EM-DAT disaster groups are ‘Natural’, ‘Technological’, and ‘Complex’. Disasters from the Complex group are marginal (14 entries). These were former famines that did not appear to be triggered by a drought event (see A Brief History of the EM-DAT Classification System). The table below shows the complete tree for the ‘Natural’ and ‘Technological’ groups, with the occurrence for each subtype. Their corresponding definitions are available in the Classification Glossary.

Classification Key Group Subgroup Type Subtype Count5
nat-bio-ani-ani Natural Biological Animal incident Animal incident 1
nat-bio-epi-bac Natural Biological Epidemic Bacterial disease 781
nat-bio-epi-dis Natural Biological Epidemic Infectious disease (General) 142
nat-bio-epi-fun Natural Biological Epidemic Fungal disease 0
nat-bio-epi-par Natural Biological Epidemic Parasitic disease 51
nat-bio-epi-pri Natural Biological Epidemic Prion disease 0
nat-bio-epi-vir Natural Biological Epidemic Viral disease 547
nat-bio-inf-gra Natural Biological Infestation Grasshopper infestation 16
nat-bio-inf-inf Natural Biological Infestation Infestation (General) 9
nat-bio-inf-loc Natural Biological Infestation Locust infestation 67
nat-bio-inf-wor Natural Biological Infestation Worms infestation 3
nat-cli-dro-dro Natural Climatological Drought Drought 804
nat-cli-glo-glo Natural Climatological Glacial lake outburst flood Glacial lake outburst flood 3
nat-cli-wil-for Natural Climatological Wildfire Forest fire 317
nat-cli-wil-lan Natural Climatological Wildfire Land fire (Brush, Bush, Pasture) 92
nat-cli-wil-wil Natural Climatological Wildfire Wildfire (General) 53
nat-ext-imp-air Natural Extra-terrestrial Impact Airburst 0
nat-ext-imp-col Natural Extra-terrestrial Impact Collision 1
nat-ext-spa-ene Natural Extra-terrestrial Space weather Energetic particles 0
nat-ext-spa-geo Natural Extra-terrestrial Space weather Geomagnetic storm 0
nat-ext-spa-rad Natural Extra-terrestrial Space weather Radio disturbance 0
nat-ext-spa-sho Natural Extra-terrestrial Space weather Shockwave 0
nat-geo-ear-gro Natural Geophysical Earthquake Ground movement 1544
nat-geo-ear-tsu Natural Geophysical Earthquake Tsunami 57
nat-geo-mmd-ava Natural Geophysical Mass movement (dry) Avalanche (dry) 5
nat-geo-mmd-lan Natural Geophysical Mass movement (dry) Landslide (wet) 30
nat-geo-mmd-roc Natural Geophysical Mass movement (dry) Rockfall (wet) 9
nat-geo-mmd-sub Natural Geophysical Mass movement (dry) Sudden Subsidence (wet) 1
nat-geo-vol-ash Natural Geophysical Volcanic activity Ash fall 249
nat-geo-vol-lah Natural Geophysical Volcanic activity Lahar 0
nat-geo-vol-lav Natural Geophysical Volcanic activity Lava flow 10
nat-geo-vol-pyr Natural Geophysical Volcanic activity Pyroclastic flow 4
nat-geo-vol-vol Natural Geophysical Volcanic activity Volcanic activity (General) 9
nat-hyd-flo-coa Natural Hydrological Flood Coastal flood 85
nat-hyd-flo-fla Natural Hydrological Flood Flash flood 831
nat-hyd-flo-flo Natural Hydrological Flood Flood (General) 2283
nat-hyd-flo-ice Natural Hydrological Flood Ice jam flood 0
nat-hyd-flo-riv Natural Hydrological Flood Riverine flood 2657
nat-hyd-mmw-ava Natural Hydrological Mass movement (wet) Avalanche (wet) 121
nat-hyd-mmw-lan Natural Hydrological Mass movement (wet) Landslide (wet) 609
nat-hyd-mmw-mud Natural Hydrological Mass movement (wet) Mudslide 79
nat-hyd-mmw-roc Natural Hydrological Mass movement (wet) Rockfall (wet) 3
nat-hyd-mmw-sub Natural Hydrological Mass movement (wet) Sudden Subsidence (wet) 1
nat-hyd-wav-rog Natural Hydrological Wave action Rogue wave 0
nat-hyd-wav-sei Natural Hydrological Wave action Seiche 0
nat-met-ext-col Natural Meteorological Extreme temperature Cold wave 311
nat-met-ext-hea Natural Meteorological Extreme temperature Heat wave 259
nat-met-ext-sev Natural Meteorological Extreme temperature Severe winter conditions 79
nat-met-fog-fog Natural Meteorological Fog Fog 1
nat-met-sto-bli Natural Meteorological Storm Blizzard/Winter storm 226
nat-met-sto-der Natural Meteorological Storm Derecho 6
nat-met-sto-ext Natural Meteorological Storm Extra-tropical storm 148
nat-met-sto-hai Natural Meteorological Storm Hail 111
nat-met-sto-lig Natural Meteorological Storm Lightning/Thunderstorms 189
nat-met-sto-san Natural Meteorological Storm Sand/Dust storm 20
nat-met-sto-sev Natural Meteorological Storm Severe weather 263
nat-met-sto-sto Natural Meteorological Storm Storm (General) 898
nat-met-sto-sur Natural Meteorological Storm Surge 7
nat-met-sto-tor Natural Meteorological Storm Tornado 296
nat-met-sto-tro Natural Meteorological Storm Tropical cyclone 2492
tec-ind-che-che Technological Industrial accident Chemical spill Chemical spill 108
tec-ind-col-col Technological Industrial accident Collapse (Industrial) Collapse (Industrial) 181
tec-ind-exp-exp Technological Industrial accident Explosion (Industrial) Explosion (Industrial) 778
tec-ind-fir-fir Technological Industrial accident Fire (Industrial) Fire (Industrial) 219
tec-ind-gas-gas Technological Industrial accident Gas leak Gas leak 61
tec-ind-ind-ind Technological Industrial accident Industrial accident (General) Industrial accident (General) 124
tec-ind-oil-oil Technological Industrial accident Oil spill Oil spill 8
tec-ind-poi-poi Technological Industrial accident Poisoning Poisoning 76
tec-ind-rad-rad Technological Industrial accident Radiation Radiation 9
tec-mis-col-col Technological Miscellaneous accident Collapse (Miscellaneous) Collapse (Miscellaneous) 305
tec-mis-exp-exp Technological Miscellaneous accident Explosion (Miscellaneous) Explosion (Miscellaneous) 220
tec-mis-fir-fir Technological Miscellaneous accident Fire (Miscellaneous) Fire (Miscellaneous) 788
tec-mis-mis-mis Technological Miscellaneous accident Miscellaneous accident (General) Miscellaneous accident (General) 275
tec-tra-air-air Technological Transport Air Air 1089
tec-tra-rai-rai Technological Transport Rail Rail 645
tec-tra-roa-roa Technological Transport Road Road 2857
tec-tra-wat-wat Technological Transport Water Water 1624

Associated Disasters

In addition to the main classification system, EM-DAT makes it possible to refer to “associated disasters” to describe disaster events in more details (see Associated Dis in EM-DAT Public Table). They represent subsequent or co-occurring hazards that may have contributed to the disaster impact. These associated disasters may not fit into the main classification system and do not have a hierarchical structure. This additional tagging system allows for a better description of disaster events, particularly multi-hazard ones. The figure below shows the main associations found in the database.

Sankey diagram of the associations between main disaster types (MT) and associated disaster types (AT) in EM-DAT. The figure only reports MT-AT associations having an occurrence >= 50 in the database. Gray band sizes between MT and AT are proportional to the occurrence of the association in EM-DAT. Last updated: September 5, 2023.

About 14% of disaster entries in EM-DAT have an associated disaster type, and only 3% mention two associated types. The most common associations are floods with landslides (24% of associations), storms with floods (21%), and storms with landslides (8%). Earthquakes are sometimes associated with landslides (4%) and tsunamis (4%) when their damage is deemed negligible compared to ground movement damage.

  1. Guha-Sapir, D. and Misson, C.: The Development of a Database on Disasters, Disasters, 16, 74–80, https://doi.org/10.1111/j.1467-7717.1992.tb00378.x, 1992. ↩︎

  2. DHA-UNDRO, IDNDR, UNEP, WFP, WHO/PAHO, USAID/FHA, IFRC, and CRED: Proposed principles and guidelines for the collection and dissemination of disaster-related data, Brussels, Belgium, 1992. ↩︎

  3. Below, R., Wirtz, A., and Guha-Sapir, D.: Disaster Category Classification and peril Terminology for Operational Purposes, Centre for Research on the Epidemiology of Disasters, Munich Re, Brussels, Belgium, 2009. ↩︎

  4. Below, R., Grover-Kopec, E., and Dilley, M.: Documenting Drought-Related Disasters: A Global Reassessment, The Journal of Environment & Development, 16, 328–344, https://doi.org/10.1177/1070496507306222, 2007. ↩︎

  5. Number of disasters that occurred at the country level in EM-DAT (1900-present) as of September 5, 2023. ↩︎