Preliminary Survey of Early Warning
Systems
Background Document in Support of the UN Secretary
General Kofi Annan Report to the General Assembly
29 July 2005
Geneva, Switzerland
Contributed by
World Meteorological Organization
Overview
In response to the first phase of the Global Early Warning Survey requested by the UN Secretary General, Kofi
Annan, WMO conducted a simple overview survey based on knowledge and experience of its ten WMO
programmes to provide feedback into the progress report of the Secretary-General to the General Assembly in
September 2005. In this report we provide our assessment of the current capabilities, major gaps and needs
related to the four stages of Early Warning Systems, including i) risk identification (observation, monitoring,
detecting), ii) forecasting and operational warnings, iii) warning dissemination, and iv) response at national to
local levels. This assessment is provided for a number of hazards including tornados, flash floods, flood (river
basin flooding), severe storms, heat waves, cold spells, tropical cyclones (hurricanes and typhoons), storm
surges, locust, forest fires, droughts, mud and land slides, air pollution, dispersion of chemical spills, volcanic
ash, nuclear accidents, through air and water.
WMO, as a specialized agency of the United Nations, works through the National Meteorological and
Hydrological Services (NMHSs) to ensure that, among other things, issues related to effective operational early
warnings for weather-, water-, and climate-related hazards are addressed effectively across political
boundaries. WMO and its 187 Members, through its 10 international scientific and technical programmes, and
its global network of three World Meteorological Centres (WMCs) and 40 Regional Specialized
Meteorological Centres (RMSCs) — operated by NMHSs, its Global Observing System (GOS), Global
Telecommunication System (GTS) and Global Data-Processing and Forecasting System (GDPFS) — provides
around the clock operational capabilities, along with international and regional collaborations and coordination
to support the early warning activities of the NMHSs at the national level. WMO’s GOS enables the
observation and collection of weather, water and climate information from around the globe. Through this
system, data are collected from 16 satellites, hundreds of ocean buoys, over 150,000 aircraft, 7,000 ship reports
and nearly 10,000 land-based stations. NMHSs make and collect observations in their countries. These
observations along with more than 50,000 weather reports and several thousand charts and digital products are
disseminated daily through the WMO GTS, which interconnects meteorological centres around the globe. The
WMO GDPFS ensures the cooperation of world, regional and national centres to process data and provide
routinely countries with analyses and forecasts, including early warnings of severe events. Based on the
analyses and forecasts provided by WMCs and RSMCs, NMHSs develop and provide early warnings adapted
to local conditions and needs, when natural hazards threaten their country. Finally, through eight RSMCs,
WMO supports its Members and international organizations to respond to large-scale trans-boundary
environmental emergencies caused by major nuclear accidents, volcanic eruptions, chemical accidents, and
wild fires.
The infrastructures of NMHSs undoubtedly constitute a considerable asset to the international community, in
their efforts to deal with disaster response. This is because they are operational 24/7 organizations that have
their government’s mandates for the issuance of around-the-clock early warnings for a wide rage of hazards
related to weather and water. Significant capabilities for observing, detecting, monitoring, forecasting and
issuance of early warning for these hazards have been developed within the NMHSs of the countries. However,
the capabilities and resources of the NMHSs significantly vary from country to country.
There are major common gaps, particularly in developing and least developed countries in the chain of early
warning system. While there is need for developing and improving sustainable technical capacity related to
observing, monitoring, detecting and forecasting, and warning issuance capabilities of the National
Meteorological Services, there are gaps in, i) linkages between the National Meteorological and Hydrological
Services and the emergency management authorities and the media, ii) alert mechanisms from national
authorities to local level, iii) availability of national to local emergency policy and preparedness plans, iv)
education and public outreach programmes and other capacities that would enable the public to know how to
respond to warnings. The following paragraphs provide a short summary of each hazard describing them, what
the current capabilities are, and the major gaps and needs related to the different stages of Early Warning
Systems.
Review of Existing Capabilities and Gaps for Early Warning for Different Hazards
Severe storms
Tornadoes, lightning, hailstorms, high wind, dust storms, waterspouts and heavy precipitation are examples of
these events.
Tornados are most common in sub-tropical to mid-latitude regions, but have killed people on every continent
except Antarctica. Tornadoes produce the strongest surface winds on Earth reaching 500 km/h. They can
impact areas extending from meters to tens of kilometres. Tornado warning lead-times if any are very short.
Detection and forecasting capabilities of tornadoes have been developed and are operational in a few developed
countries like the United States, where warnings are issued with lead-times of up to 15 minutes. However, there
are significant gaps in such capacities in developing and least developed countries.
Hailstorms - During severe hailstorms, hailstones can be 10 cm or more in diameter and can fall at speeds of
150 km/h or more. Hailstorms occur mostly in the mid-latitudes in heavy thunderstorms and can lay a path of
destruction from a few to tens of kilometres. Warning lead-times can vary from none to a few hours, as
forecasting hail is challenging owning to their localized nature. In developing and least developed countries
there are major gaps along the entire chain of the early warning system.
Severe windstorms occur throughout the middle latitudes and are generally most frequent and intense during
winter with gales lasting up to several days and extending to 1,000 km or more. Severe storms are observed
and detected through the Global Observing System (GOS) of WMO and are communicated, through the WMO
Global Telecommunication System (GTS), to 16 Regional Specialized Meteorological Centres, who develop
forecasts and bulletins and disseminate to NMHSs in their region. NMHSs issue severe winter storm warnings
in the country.
Sand and dust storms affect mainly desert areas and can range in size from 10’s to 1000’s of kilometres.
Warning lead times are normally up to 3 days and are based on Satellite and ground observational data but
these capabilities are not yet operational.
Heavy Precipitation (rain and snow) can affect areas from tens to hundreds of kilometres. Warning lead-times
range from a few hours to a day. Early warning capabilities exist mostly in the developed and some developing
countries but significant gaps exist in the least developed countries.
Flash floods
Flash floods are localized events, which occur as a sudden response to severe precipitation or ice melt and
occur in almost all regions. Observation, monitoring and forecasting technologies exists in a few developed
countries like the United States, Canada and Central Europe; however, these capabilities are inadequate in
other countries.
Floods (river basin flooding)
Floods are among the most common and most devastating natural disasters and affect all regions. Technologies
for observing, detecting, monitoring and forecasting of floods exist and have been demonstrated, however,
these capabilities can be further enhanced through stronger integration of meteorological and hydrological
forecasts. These capacities differ among countries and their National Meteorological and Hydrological
Services. In countries with functioning flood warning services, dissemination of forecasts and warnings could
reach to the district and sub-district levels; however, major gaps exist in reaching the community level. Within
developing and least developed countries, there are gaps along the entire early warning system chain from
observation to the ability to respond at the community level.
Heat waves
Heat waves are prolonged periods of extreme temperature and humidity that persist for a few days to weeks.
They are most deadly in mid-latitude regions, especially urban areas. They affect all regions and can extend
from hundreds of kilometres to portions of a continent. Computer weather models and Heat Health Warning
Systems (HHWS) are used to forecast this hazard and provide warning lead-times of 1-3 days. Major gaps exist
because short-term heat and health warnings are only issued in a limited number of cities and countries and
where these capabilities are available, there is a lack of understanding of what the heat wave indices mean and
what response is to be taken. Additionally, in most countries there is a lack or absence of coordination from
national to local civil authorities.
Cold spells
Loss of life resulting from cold spells are greater among people aged 60 or older in regions with warmer
winters, where people are less likely to have heating. Maximum temperatures of 4 to 5°C below normal
resulted in more than 2 500 fatalities in India in December 2002. Cold spells in Mongolia killed over 750 000
cattle during the winter of 2001-2002. Cold spells are prolonged periods of extreme cold temperatures from
days to weeks. Warning lead times are based on weather observations and 1-3 day forecasts. Warnings are only
issued in a limited number of cities and countries.
Tropical cyclones
Tropical cyclones (also known as hurricanes and typhoons) are spawned in the warm tropical oceans with the
strongest having sustained winds greater than 195 km/h and wind gusts greater than 280 km/h. Some can grow
to a radius of more than 300 km before they decay, over either land or cooler water. Tropical cyclones have the
potential to leave swath of destruction from strong winds and heavy rainfalls. In 1998, Hurricane Mitch struck
Nicaragua, Honduras and Guatemala: 11 000 dead and widespread flooding. Through the World
Meteorological Organization’s operational Global Tropical Cyclone Warning System, including an operational
observing network, 6 tropical cyclone Regional Specialized Meteorological Centres (RSMCs), 5 Tropical
Cyclone Warning Centres and the National Meteorological Services, tropical cyclone are observed, monitored
and forecasted every day of the year, in all regions. Forecasts of severity, path and land fall are issued around
the clock by the RSMCs and issued to the National Meteorological Services of countries at risk, who then issue
the warning for their countries with warning lead-times of at least 24 hours. There are continued efforts to
improve further the forecasting capabilities (tropical cyclone tracks, etc). While in many countries, these
warnings are integrated in the emergency preparedness and response plans, significant gaps exist in the
developing and least developed countries. Also, there is need for continued improvement of tropical cyclone
forecasting capabilities.
Storm surges
Storm surges are experienced in all coastal regions and can affect areas from tens to hundreds of kilometres and
are mostly associated with tropical cyclones. Warning lead times are at least 24 hours. Forecasting of storm
surges and the associated coastal flooding are generally carried out by national meteorological and hydrological
services and gaps are found in countries where their National Meteorological and Hydrological services have
limited capacity. Overall, there is need for building technical capacity for forecasting of storm surge and related
coastal flooding and linking this information with the emergency preparedness and response authorities,
particularly in the developing and least-developed countries. Bangladesh serves as another excellent example in
its decade-long effort to establish integrated early warning services to safeguard its population from hazards as
a result of tropical cyclones, storm surges, tidal and riverine floods. It is mainly due to the largely successful
implementation of improved observational and communication systems, close cooperation between the
NMHSs, development of nationwide alert mechanisms built on a network of over 5,000 volunteers and other
alert mechanisms to deliver critical warnings and advisories to communities at-risk. This mechanism combined
with culturally-based educational and preparedness programmes and emergency planning activities such as
building of shelters in the coastal areas have proven to be highly effective in saving many lives.
Locust
Locust swarms are normally experienced in the regions of Saharan and Sub-Saharan Africa, South West Asia,
and regions of Australia. General Warning bulletins and advisories are produced mainly through National
Locust Control Centres and only a few National Meteorological Services are involved in their dissemination.
Warning lead times are on the order of less than a month for an initial outbreak to 3 to 6 months in a plague.
Potential for locust swarms are anticipated through detection of their food sources via utilization of satellite and
ground based observations. Warning capabilities can be improved if these capabilities are linked to operational
weather forecasts. However, there are significant gaps for the developing and least developed countries as there
is need to build technical capacity within the National Meteorological Services to be able to link and provide
these capabilities to the National Locust Centres. Other gaps include integration of warnings with prevention
strategies to take appropriate control measures to reduce the swarms. Finally, since locust swarms are major
regional issue, enhanced regional coordination can help in reducing the risk of locust swarms across national
boundaries.
Forest fires
All regions experience forest fires and the devastation can extend from a few to thousands of kilometres in size.
Warnings are based upon a fire weather index or fire danger rating and lead-times for the highest fire danger
are normally 4-6 hours, however, using forecasted weather data, as much as 14 days of early warning can be
provided. Warning lead-times are based on meteorological monitoring and forecasting along with satellite
imagery and ground based WMO GAW aerosol measurements. Numerous early warning systems for wild land
fire are currently in operation; however no internationally accepted system exists. Within the least developed
countries, there are major gaps along the entire early warning system chain from observation to the ability to
respond at the community level.
Droughts
Droughts can be experienced in all regions and can affect areas from tens to thousands of kilometres and can
persist for months to years. The primary cause is deficiency of rainfall and timing, distribution, and intensity of
this deficiency in relation to existing reserves, demand and water use. Temperature and evaporation may
aggravate the severity and duration. Early warning capabilities can range from a few weeks to several months
and are based upon current observations that are integrated with meteorological forecasts. Most National
Meteorological and Hydrological Services monitor drought and or produce some kind of drought index but
collaboration varies by country. Bulletins and advisories are only starting to be issued mainly by the developed
countries. At the national and local level, only a few countries have drought plans that integrate drought
monitoring with policy actions.
Mud and landslides
Heavy rain or snowmelt often triggers mudflows and landslides, and steep terrain is usually involved.
Landslides send large amounts of earth, rock, sand or mud flowing swiftly down mountainsides, especially
those denuded by wild land fires. Mudflows are essentially super wet, fast-moving landslides. The resulting
river of mud, reaching 50 km/h or more, accumulates and hurls trees, boulders, other massive debris that
crushes with tremendous impact. Worst natural disaster ever in Venezuela occurred in 1999 where landslides
and mudflows shot down Avila Mountain, washing away towns, killing an estimated 15,000 to 20,000 people,
and resulting in almost US$ 2 billion in damages. Early warning capacities exist only in a few developed
countries where warning lead-times range from none to a few hours.
Chemical spill dispersion
All regions can be affected by chemical spills. They are experienced mainly in the vicinity of industrial
transportation corridors and can extend from local to hundreds of kilometres. Warning lead times are from
minutes to hours and are based on observational data, satellite imagery and meteorological and oceanographic
forecasts. Capabilities in observation, monitoring, forecasting, and dissemination vary by country but major
gaps are found in the least developed countries.
Volcanic ash dispersion
Volcanic ash is experienced mainly in the mountainous volcanic regions but can affect large areas on the order
of hundreds to thousands of kilometres. Warning lead times are generally tens of minutes to hours and are
based on observational and forecast data. Through the global network of volcano observatories, which is
coordinated by the World Organization of the Volcano Observatories, only a small percent of the 500 known
active volcanoes are monitored, and not all continuously. A number of ground-based, airborne, and space based
observation of volcanic ash cloud are used by WMO Members but their number and frequency need to be
enhanced and new sensors need to be developed.
These warning are crucial for the airline industry and International arrangements for monitoring and providing
warnings to aircraft including the communications links between the various entities should be improved.
Nuclear accident dispersion
Radiation from nuclear accidents can affect areas from tens to thousands of kilometres. Warning lead-times can
range from tens of minutes to hours. Early warning capabilities in all four stages exist at the international level
but vary significantly at the country and local level especially in the least developed countries.