Setting up Early warning system
Early warning system
Purpose: To detect, forecast and when necessary issue alert related to impending
disaster.
Output indicators
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Local community is aware of hazards likely to face
Community interprets early warning symptoms appropriate and timely action
to minimize loss of live and property
Indigenous knowledge on early warning identified
Public address system each community or village
Early warning systems
The purpose of early warning systems is to detect, forecast, and when necessary, issue
alerts related to impending hazard events. In order to fulfill a risk reduction function,
however, early warning needs to be supported by information about the actual and
potential risks that a hazard poses, as well as the measures people can take to prepare for
and mitigate its adverse impacts. Early warning information needs to be communicated in
such a way that facilitates decision making and timely action of response organisations
and vulnerable groups. Here below you are seeing how a early warning system orginates
or where from the inputs for early warning are got from. (Please note NMS means
National Meteorological Service)
Early warning information comes from a number of sources:
1. Meteorological offices
2. Ministry of Health (for example, disease outbreaks)
3. Ministry of Agriculture, Irrigation and Livestock (for example, crop forecasts);
4. Local and indigenous sources;
5. Media sources (Radio, TV, Newspaper)
6. Internet early warning services.
All too often, those who need to heed early warning alerts have little faith in the
warnings. This may be due to a human inclination to ignore what appears inconvenient at
the time, to a general misunderstanding of the warning’s message or to frustration with
yet another false alarm. When developing public early warning systems, planners must
account for the public's perceptions of warnings, their experience related to reacting to
warnings in the past, and general public beliefs and attitudes regarding disasters and
public early warnings.
Many countries use the Global Telecommunications System (GTS) of the World
Meteorological Organization (WMO) for the transfer of real-time meteorological data.
More recently, some hydrological data from a number of projects were added to the
system. Even with these advances in remotely sensed data and their use, inadequacy of
data remains the biggest weakness in establishing a viable flood forecast programme for a
river basin or for a country
Even though national governments are ultimately responsible for issuing timely public
warnings, Afghan National Disaster Management Authority can play a supporting role. It
with the help of Provincial Disaster Management Committee and District DMC can
raise local awareness of the hazards to which a community is exposed and assist local
organisations and vulnerable populations with interpreting early warning information and
taking appropriate and timely action to minimise loss and damage. Afghan National
Disaster Management Authority’s efforts to build these capacities should complement
local indigenous capacities and knowledge related to disaster early warning and alert.
(EOC means Emergency Operation Centre – that is set up on the on set of or
prediction of Disaster)
Detecting and Forecasting Disasters
Flash flood
 Satellite evidence: Satellite imagery can indicate the presence of larger and
smaller-scale systems associated with heavy rainfall.
 Radar evidence: Radars graphically display precipitation on a map. Radar can
show the location of the intense rainfall cores associated with deep moist
convection, and estimate the duration of rainfall. Radar can also track the
evolution of convective systems over time. Forecasters are able to watch existing
cells intensify, and see when new cells begin to develop aloft. Animation of radar
provides specific information on the movement of convective systems and helps
in the assessment of the flash flood threat.
 Ground evidence: Rain gauges provide the most accurate method of measuring
rainfall at a single geographic point. To have operational value, the rain gauge
report must be available in real time, and automated reporting networks are
increasing. Some places that are subject to frequent floods are protected by
warning systems that are activated when stream depths or rainfall amounts exceed
certain levels. In a typical system automated rain and/or stream level gauges
transmit information to a central computer which then activates an alarm, giving
critical decision makers enough time to enact emergency measures.
The hydrometeorological network is the key requirement for most flood forecasting. In
particular, precipitation and stream-flow data are needed. If snowmelt is a factor in
flooding, then measurements of snow water equivalent, extent of snow cover, and air
temperature are also important.
Important questions that are borne in mind in flood forecasting network
Are the rainfall and stream gauge (hydrometric) data networks satisfactory in sampling
rainfall (intensity and spatial distribution) and streamflow response for the river basin?
Are stream gauges operating properly, and are they providing accurate conditions of
water level and streamflow?
Are data communicated reliably between the gauge sites and the forecast centre?
How often are observations taken, and how long does it take for observations to be
transmitted to the forecast centre?
Are data available to users who need the information for decision making?
Are the data archived for future use?
Are the data collected to known standards, is the equipment properly maintained and
calibrated, and are the data quality controlled?
There are many types of communication technologies that can be applied to transmit
data from sites in remote locations to the forecast centres. The most common form of
data communication is by telephone. However, telephone lines frequently fail
during severe flood events. More reliable but potentially more expensive forms of data
communications are satellite, line of site radio, cellular radio and meteor bursts.
Appropriate communication line should be established to have an effective flood
forecasting system in addition to data collection instruments such as rain gauge, Flow
meter etc.,
Land (Mud) Slide
There are a lot of disputes over the precise definition of flash floods and debris flow
(Land Slide) disasters. We considered a flash flood is a flood from the river (rivulet or
torrent) in mountainous areas. Debris flow includes a mix of solid and liquid materials,
occurring on vales and slope. Debris flow is also taken to include the blending of gas,
water and soil (relaxed solid) from hyper-concentrated flows in mountainous areas.
Deforestation, fires and erosion of materials combined with saturated soils can lead to
landslides, mudflows and other threats to human settlements.
Flash flood and debris flow disasters are usually considered as a bane to human beings
and social economic systems, but not all flash floods and debris flows result in disaster,
particularly in sparsely populated high mountainous region. Many developed countries
try to alleviate losses caused by flash floods and debris flows but still cannot avoid this
kind of disaster completely. In Afghanistan, with big mountainous areas flash flood and
debris flow disasters can result in serious losses, with significant effects on economic
development.
Currently, international experts generally accept the measure of torrent classification and
hazardous zone index by Austrian scientist Oliches, which is scientific and feasible. By
analysing danger level and degree of flash flood or debris flow disaster in ditch or
alluvium, red zone, yellow zone and white zone are classified in order that government
and people may take measures to control the disaster. Its main technique is to investigate
and adopt sample to analyze the concrete ditch or torrent, namely adopting 9 indexes and
51 concrete factors to obtain the danger index. To sum up it is possible to classify the
areas into flash prone regions and less prone regions. Just base on the amount of rainfall
or snow, using the computer model using GPS code it is possible to come to the
conclusion of likelihood of a Flash flood and debris flow hitting a region or place.
Real-time forecasting technique of flash flood can be forecasted with hydrometeorological and runoff model. Here computer based models using critical
precipitation and rainfall analysis, man observation and equipment monitor are studied to
give an accurate prediction. These research have reached high degree of sophistication
and adaptability in advanced countries such as US, China and India. In Afghanistan it is
in the initial stages.
Earthquake
 Satellite thermal remote sensing: Rise in land surface temperature (LST) before
an impending earthquake has been used to detect earthquake to 90 % accuracy.
This is based on the concept that stress accumulated in rocks in tectonically active
regions may be manifested as temperature variation through a process of energy
transformation. Satellite thermal remote sensing has emerged as a potential tool in
detection of pre-earthquake thermal infrared (TIR) anomaly in land surface
temperature in and around epicentral regions.
 Satellite Electromagnetic Detection: It is understood that Earth quake results in
the release of energy from the earth. So the change in the electromagnetic field
near the epicenter of earth quake is detected by the Satellite eleromagnetic
detector. Earth based magnetic sensers too have been tested in this regard and
found to be useful
 Electrical Signal based prediction: Now Russian Scientist have come out with
the finding of predicting earthquake using electrical signal detectors. If these
instruments are kept in a place, earth quakes can be detected atleast 2 days in
advance.
There are companies who offer the services of Earth quake forecast for a price. For
example the following company whose website address is given below gives the forecast
with 100 % accuracy before 3 days of occurrence of earth quake. The company assures to
re-fund the money if their forecast is wrong. Charge for this service is 3000 USD per
year.
http://www.earthquakeforecast.com
Traditional Predictions
It has been found that pet animals such as cats and dogs and domesticated animals such
as cows and buffalo behave strangely before disasters such Earthquake and Tsunami. It is
said that just hours before the disasters Tsunami dogs and cats ran to the highest place.
Buffalos made strange sounds and ran up the hills. Even before the earthquake in Gujarat
in India the dogs made usual sounds and behaved abnormally. Though there is no
scientific proof to those who argue Traditional experience based prediction, it has come
to existence by the word of mouth.
For example, in September 1994, in Papua New Guinea, on the island of New Britain,
community elders who had survived the Rabaul volcanic eruption of 1937, noticed and
acted upon several strange "early warning" phenomena that were similar to those that
preceded the 1937 eruption. This phenomena included: "ground shaking vertically instead
of horizontally, megapod birds suddenly abandoning their nests at the base of the
volcano, dogs barking continuously and scratching and sniffing the earth, and sea snakes
crawling ashore." This indigenous experience, combined with volcano preparedness
awareness raising and evacuation planning and rehearsals that were initiated a decade
earlier when the Rabaul volcano threatened to erupt again, undoubtedly contributed to the
low death toll in September 1994, (three people died during the evacuation), despite the
extensive damage to the city caused by the ash fall
Centralisation and decentralisation of EWS
When analyzing who executes the two initial phases of the early warning systems,
namely, monitoring and forecasting, one can see two trends, centralised systems where a
national-type agency carries out these functions, and decentralised systems where these
tasks are carried out by other agencies, municipal workers and volunteers at the more
local level. For example, in Central America, the national meteorological agencies
operate early warning systems for hurricanes and for floods, including the emission of the
warning to the media. Such systems are set up and operated by these institutions.
In contrast, national disaster reduction agencies, international organisations, and nongovernmental organisations have been implementing decentralised systems in small
basins, where communities carry out all phases, including the response. In such systems,
city halls are coordinating most of the activities, and are connected to the national
emergency agency via a radio network that is used to communicate all information
within the system.
While decentralised systems operate using much simpler equipment and are thus less
precise, such systems rely on a network of people-operated radios to transmit information
regarding precursors to events or warnings. The trade off gained from losing precision to
monitor and forecast events is gained by being able to transmit other very useful
information, generally related to social issues, such as medical needs, information
regarding relatives or processes, or the solution of such problems as the fixing of power
lines when they fail, or acquiring heavy machinery to reopen a road which might be
blocked by a landslide. So far, community-operated systems have been mostly applied in
the case of floods, especially in small flood basins.
Flood Warning
At the time of Disaster such as flood danger flags are hoisted on the building to warn the people
four warning levels:
• Warning
level 1 (green): no danger
level 2 (yellow): medium danger
• Warning level 3 (orange): high danger
• Warning level 4 (red): very high danger
• Warning
The same signals or flags are used in the coastal areas to warn the fishermen about the
impending storm. The District DMC can use these flag signals to warn the people about
the disasters
Using the rainfall data it is possible to map the regions of high threat and low indicated
by the same colours as given above . The early warning maps are refreshed every 3 hours
after updated precipitation forecasts are available. They provide information about the
flood danger during the forthcoming 24 hours in one map and the hours 25 to 48 in a
second map.
Early warning
Early warning systems have limitations in terms of saving lives if they are not combined
with “people-centred” networks. To be effective, early warning systems must be
understandable, trusted by and relevant to the communities that they serve. Warnings will
have little value unless they reach the people most at risk, who need to be trained to
respond appropriately to an approaching hazard. ANDMA and DMCs at Provincial level
therefore, gives its full support to the development of warning systems but stresses the
importance of:
 establishing local networks that can both receive and act on warnings and that
raise awareness and educate communities to take action to ensure their safety;
 utilizing local networks to develop warning systems progressively so that they
meet the needs of the communities and situations for which they are designed;
taking a multi-hazard approach to ensure sustainability by providing active alert,
awareness and relevance
Early Warning System
The traditional framework of early
warning systems is composed of three
phases (see the figure by the side):
1. Monitoring of precursors
2. Forecasting of a probable event,
3. Notification of a warning or an
alert should an event of
catastrophic proportions take
place.
An improved four-step framework being
promoted by national emergency
agencies and risk management
institutions includes the additional fourth
phase: the onset of emergency response
activities once the warning has been
issued. The purpose of this fourth
element is to recognize the fact that there
needs to be a response to the warning,
where the initial responsibility relies on
emergency response agencies (see figure).
Effective early warning systems require
strong technical foundations and good
knowledge of the risks.
An early warning has no effect without
early action. Numerous examples
illustrate how reliable information about
expected threats was insufficient to avert
a disaster, including Cyclone Nargis,
Hurricane Katrina, and the food crisis in
Niger. Many people died due to lack of
proper communications and transport
facilities.
At the shortest timescales, that action
could be evacuation. On the longest
timescales, early action means working
closely with local communities to assess
and address the root causes of the changing risks they face. Houses on stilts, planting
trees against landslides, dengue awareness and prevention campaigns, water catchment
systems and millions of other risk reduction measures can be taken. Early action also
includes updated contingency planning and volunteer mobilization. In terms of
geographic range, early action can take various forms: If a large flood is expected, at the
most local scale a community can protect its main water well from contamination.
At country level a ANDMA can mobilize human and financial resources ahead of the
disaster to assist the DMCs at Provincial level to reduce casualties the impacts and even
preventing loss of life altogether. The more we act upon the warnings on the longest
timescales, by identifying communities at risk, investing in disaster risk reduction, and
enhancing preparedness to respond, the more lives and livelihoods can be salvaged at the
shortest timeframes when a flood does arrive. Similarly, better links to global and
regional knowledge centres and standardized procedures to get the information to the
right place will facilitate more effective action at the most local level.
Guiding principle 1: Prepare for the certain and the uncertain
It is certain that climate change is happening and will lead to more weather extremes
melting glaciers and sea level rise. That in itself is a strong incentive for increased early
action through disaster preparedness. We have long helped communities to prepare for
the threats they know. Climate change requires us now to help prepare communities for
threats that are unpredictable in both severity and nature.
The focus of our preparedness effort will be on increasing public awareness of the rising
disaster risk; organising communities to respond and recover better from disaster;
improving community resilience to reduce the impact of disaster shocks and developing
external partnerships with knowledge centres, governments and other civil society
organizations to address the increased risks.
To be more precise on the exact impacts of climate change is difficult. Typically, the
longer in advance a warning appears, the less precise it will be. A few hours in advance,
we usually know quite well where and when a large storm will hit. However for such a
warning to be actionable, investment must be made well in advance to create a
comprehensive emergency management system. With a warning period of a few days, a
storm forecast leads to immediate disaster preparedness action – identifying evacuation
routes, evacuation centres, protecting assets and mobilizing community organizers for
immediate response.
However, a longer term warning (months or years in advance) of the changing
nature of storm risk allows us to expand our disaster risk reduction actions, including
helping communities plant trees to stabilize hillsides, organizing themselves to respond
better to warnings, building storm-resistant houses or advocating for constructing storm
shelters. Knowing that a risk is higher than normal demands a higher level of investment
in preparing capacity to take early actions that will be useful regardless of when and
where the disaster strikes.
Using such risk information may also mean that we sometimes get it “wrong” – for
instance when a forecast predicts a 80 per cent likelihood that there will be Heavy rains
with force winds in a certain time and place. We know that while very likely to happen,
there’s no certainty. Indeed, for 20 per cent of these cases, we actually expect the
predicted condition to not happen. We should not hide that uncertainty when we promote
early action: an honest description of what we know and don’t know about the future
should be a key component of our communication to all stakeholders, and an important
consideration in how we assess and address the risks.
Guiding principle 2: Communication for action is the key. Early warnings are
irrelevant if they are not received, understood and trusted by those who need to act. New
sources of scientific information provide us with new opportunities, but also continuously
raise questions. What does it mean to have a higher level of risk? Should the Provincial
DMCs act, or wait? When does the risk get so significant that we need to put the DMCs
on earlyaction? There is a need to transform scientific information, which is often
complex and inthe form of maps or percentages, into simple and accessible messages that
would allowpeople at risk to make sensible decisions on how to respond to an impending
threat. This requires firstly a continuous dialogue through collaboration between DMC
staff and Governors and knowledge centres at national, regional and global levels. It also
requires expanded investment in disaster preparedness at all levels – community, local
and national.
Only with such an investment can the risk knowledge produced by specialized centres be
made available to vulnerable people exposed to increased climate change disaster risk.
Even then, for that information to be effective, communities need to have the resources
and capacities necessary to respond and react to it. Good communication is one thing,
having the ability to use the information is another.
Example of early warning
Floods
Before Years of
 Increasing risk of extreme
Flood What should be
rainfall due to climate
done
change
 Increasing risk of extreme
rainfall due to climate
change
Before Months of
Flood what should be
done
Forecast of strongly aboveaverage rainfall for the coming
season
Before weeks of
Flood what should be
done
High ground saturation and
forecast of continued rainfall
leading to high probability of
floods
Before days of Flood
what should be done
Heavy rainfall and high water
levels
upstream, likely to result in
floods
Flood water moving down the
river to affected areas
Before Hours of Flood
what should be done
Example of early action
Continually update risk maps
and identify changing
vulnerable groups, recruit
additional volunteers, establish
new areas of work, work with
communities to reduce risk
through concrete actions like
reforestation, reinforcement of
houses, etc.
Revisit contingency plans,
replenish stocks, inform
communities about
enhanced risk and what to do
if the risk materializes, e.g.
clear drain.
Alert volunteers and
communities, meet with other
response agencies to
enable better coordination,
closely monitor rainfall
forecasts
Prepare evacuation, mobilize
volunteers, get warnings and
instructions out to
communities at risk
Evacuate
The four elements of people-centred Early Warning Systems (EWS)
A complete and effective, people-centred early warning system – EWS – comprises four
inter-related elements, spanning knowledge of hazards and vulnerabilities through to
preparedness and capacity to respond. A weakness or failure in any one of these elements
could result in failure of the whole system. Best practice EWS also have strong interlinkages between all elements in the chain. While good governance and appropriate
institutional arrangements are not specifically represented on the «four element diagram»,
they are critical to the development of effective early warning systems. Good governance
is encouraged by robust legal and regulatory frameworks and supported by long term
political commitment and integrated institutional arrangements. Major players concerned
with the different elements should meet regularly to ensure that they understand all of the
other components and what other parties need from them.
Risk Knowledge: Risks arise from both the hazards and the vulnerabilities that are
present. What are the patterns and trends in these factors? Risk assessment and mapping
will help to set priorities among early warning system needs and to guide preparations for
response and disaster prevention activities. Risk assessment could be based on historic
experience and human, social, economic and environmental vulnerabilities.
Warning Service: A sound scientific basis for predicting potentially catastrophic events
is required. Constant monitoring of possible disaster precursors is necessary to generate
accurate warnings on time. Approaches that address many hazards and involve various
monitoring agencies are most effective.
Communication
and
Dissemination:
Clear
understandable warnings
must reach those at risk.
For people to understand
the warnings they must
contain
clear,
useful
information that enables
proper
responses.
Regional (Which part of
the world region), national
(ANDMA)
and
community
level
communication channels
(DMC) must be identified
in advance and one
authoritative
voice
established.
Response Capability: It is essential that communities understand their risks; they must
respect the warning service and should know how to react. Building up a prepared
community requires the participation of formal and informal education sectors,
addressing the broader concept of risk and vulnerability.