Tropical Cyclones in Tanzania: Cyclone Jobo

Are hurricane, typhoon and cyclones different?

Hurricanes, typhoons and cyclones are the same weather system called different names depending on what part of the world they develop. In the Atlantic Ocean and north Pacific Ocean tropical storms are referred to as Hurricanes, in the Indian Ocean and south Pacific Ocean they are Tropical Cyclones and in the northwest Pacific Ocean they are Typhoons.

Hazards associated with tropical cyclones

Heavy rainfall, strong and damaging winds, storm surge, large waves, lightning and even tornadoes are associated with tropical cyclones. Heavy rainfall can lead to cascading hazards such as floods and landslides. Further devastating floods can be caused by a storm surge, which is a rise in the sea level caused by strong winds and atmospheric pressure during a tropical cyclone.

What's with the name?

One of the many questions and comments I come across on social media is related to the name of cyclones, hurricanes or typhoons. So why name tropical storms and where do the names come from? 

Naming tropical cyclones makes them easier to be identified and communicate warnings to the media and communities at risk. Not many of us would remember technical names and numbers if they were used to name tropical cyclones! 

A rotating list of tropical cyclones is maintained by the World Meteorological Organization for each tropical cyclone basin. A storm name is retired if it is deadly and has caused fatalities and widespread destruction. One such name is Hurricane Katrina, a Category 5 hurricane which affected the Bahamas, Cuba, Eastern United States and Eastern Canada resulting in over 1,800 fatalities and widespread destruction in 2005.

The names for the southwest Indian Ocean including the east coast of Africa, contains three lists validated by the Tropical Cyclone Committee (TCC). During each cyclone season, the first tropical storm begins with the letter 'A' from the list. The only exception is when a tropical storm develops over the southeast Indian Ocean and moves to the southwest Indian Ocean.

 

Southwest Indian Ocean Tropical Cyclone Names (Source: World Meteorological Organization)

To find out more about more about tropical cyclone names including the list for other tropical storm basins, visit the World Meteorological Organization website. 

Tropical Cyclone Classification

Each cyclone basin uses a different classification. The image below shows these classifications.

Tropical cyclone classifications (Source: World Meteorological Organization)

Tropical Cyclones in Tanzania

Tropical cyclones are rare in Tanzania. By now you have probably heard of the two significant cyclones to affect the country. The Lindi Cyclone resulted in 34 fatalities after it made landfall in Lindi on 15 April 1952 with estimated wind speeds of 117km/h (110mph) (Stephen M. Blumel, The Tanzania hurricane of 14-16 April 1952, National Weather Digest). This cyclone was equivalent to a Category 3 hurricane.

The Zanzibar Cyclone made landfall over Zanzibar on 14 April 1872. Both cyclones caused devastating impacts including damage or destruction of houses, hospitals, the harbour, boats, infrastructure including bridges, roads, electricity, telephone and telegraph services and agriculture crops and plantations  (Hellen E. Msemo, Declan L. Finney and Samwel I. Mbuya, Weather – Month 9999, Vol. 99, No. 99, Forgotten accounts of tropical cyclones making landfall in Tanzania).

In April 2016 heavy rainfall from the remnants of Cyclone Fantala resulted in floods which caused 2 fatalities in Zanzibar and 12 fatalities in the Kilimanjaro and Arusha regions. In addition, 420 people were displaced and 3,330 houses were destroyed in Zanzibar. 13,933 people were displaced and 315 houses were destroyed in the Kilimanjaro and Arusha regions (Kai, K.H., Ngwali, M.K. and Faki, M.M. (2021) Assessment of the Impacts of Tropical Cyclone Fantala to Tanzania Coastal Line: Case Study of Zanzibar. Atmospheric and Climate Sciences, 11, 245-266).

Cyclone Jobo

Tropical Cyclone Jobo formed on 21 April over the southwest Indian Ocean. The maximum sustained wind speed recorded was 111km/h (69mph) on 21 April, making it a Tropical Cyclone (weak Category 1 Hurricane on the Saffir-Simpson Scale). Jobo weakened over the next few days to become a Severe Tropical Storm (Tropical Storm on the Saffir-Simpson Scale). 

It was forecast to make landfall over the east coast of Tanzania on 25 April with maximum sustained winds of 65km/h (40mph) and weaken further. The maximum storm surge height forecast for Tanzania was 0.2m. Heavy rainfall, strong winds and storm surges were expected to affect Aldaba (Seychelles), Comoros, Mayotte and Tanzania. In preparation, fisherman in Tanzania were warned to suspend fishing activities and warning advisories were issued by the Tanzania Meteorological Agency.

On 25 April Cyclone Jobo made landfall over at Pwani, Tanzania as a Tropical Disturbance (Tropical Depression on the Saffir-Simpson Scale) with sustained winds of 46km/h (29mph). It weakened further while moving inland and dissipated.

Fortunately, no fatalities or significant damage has been reported.  

Cyclone Jobo Track Map on 22 April (Source: JTWC)

Satellite image of Cyclone Jobo on 22 April (Source: JTWC)

Cyclone Jobo Track Map (Source: JTWC)

Satellite image of Cyclone Jobo on 24 April (Source: JTWC)

Satellite image of Cyclone Jobo on 24 April (Source: JTWC)

Final Warning Track Map of Cyclone Jobo (Source: JTWC)

What you should do to prepare for future tropical cyclones?

Below are a few tips to help you prepare for tropical cyclones in the future:

• Tune into reliable and official weather warnings and advisories. Make sure you monitor and keep up to date with the latest information. Forecasts and situations can change.
• Follow advice from official government sources and experts in the field. Remember, at times like these, rumours can be dangerous!
• Be aware of your risk. Are you at risk from flooding, landslides, storm surge or destruction from high wind speeds? 
• Create a personal disaster plan (where to go when asked to evacuate, family rendezvous point, essential and useful contacts, actions you will be required to take etc.). 
• If you have a business, ensure you have a Business Continuity Plan (BCM).
• Know how to shut off utilities including gas, electricity and water. Remember only turn off utilities if it safe to do so.
• Create a grab bag containing essential items such as regular medication, spare clothes, toiletries, money and cards, keys, mobile phone chargers, a list of useful contacts, first aid kit, torch and batteries, essential documents (passports, property and insurance) and food for your pets. Don't forget a hard copy of your disaster plan!
• Be ready to evacuate. If you are asked to evacuate by officials, do not ignore their advice. Be aware of where the community evacuation centres are located.
• Charge your mobile phones beforehand. 
• If you have generators, make sure it works and has enough fuel.
• Stock up on essential items such as food, water and fuel.
• Check on neighbours, particularly the vulnerable.
• Secure items which can become lethal debris during a cyclone.
• Take refuge in an interior room away from windows.
• If you do not feel safe, seek alternative shelter. 
• Maintain visual observations of your surroundings to check for hazards such as  flooding.
• If flooding has occurred and evacuation is not possible, stay in a high place with a means of an escape.
• Never walk in flood water, just 15cm of fast flowing can knock you off your feet!
• Flood water can also be contaminated, so try to avoid contact with it. Always wash your hands if you do come into contact with it. 
• Never drive through flood water. It takes only 30cm of flood water to move a car and 60cm to sweep away most cars.
• Have you taken your pets and livestock welfare into consideration? Make sure you plan ahead to keep them safe.
• Do not put yourself and others at risk!

Final remarks

With increasing technology specifically social media, rumours during disasters are unfortunately unavoidable. It is extremely important to always follow advice from reliable sources such as the government and experts in the field.

In April 2019 Cyclone Kenneth made landfall in Mozambique causing widespread destruction. Kenneth was forecast to make landfall in southeast Tanzania prompting numerous people to evacuate their homes. Tanzania had a lucky escape as a result of the cyclone changing direction. It is unfortunate that rumours and misinformation were being spread over social media. I came across posts claiming 'Tanzanians are scared of a little wind which is why they are evacuating', 'the storm is over exaggerated or a hoax'. 

It is extremely dangerous and potentially life threatening to underestimate the power of a cyclone. There are countless examples from around the world of the devastation and fatalities they are capable of causing. Spreading misinformation and mocking a population for making the right decision might cause them to become more reluctant to prepare for hazard in the future. It is important to remember that evacuation may cause inconvenience, but it saves lives!

With the potential impacts of climate change and increasing risk and vulnerability, a cyclone making landfall in Tanzania has a potential to cause fatalities and widespread destruction in coastal cities and towns such as Dar es Salaam. 

Always be prepared for disasters!

Useful websites

Global Disaster Alert and Coordination System (GDAC)

Joint Typhoon Warning Center

Pacific Disaster Center

Tanzania Meteorological Agency

World Meteorological Organization

If you have any questions, feel free to send me a message!

Tropical Cyclone Jobo

Tropical Cyclone Jobo formed on 21^st April over the south Indian Ocean. The maximum sustained wind speed recorded was 111km/h (69mph) on 21^st April, making it a Tropical Cyclone (weak Cat 1 hurricane on the Saffir-Simpson Scale).

Jobo has now weakened to a Severe Tropical Storm (Tropical Storm on the Saffir-Simpson Scale) with current maximum sustained wind speed of 93 km/h (58 mph). It is currently positioned at -10.4S, 46.5E and moving at a speed of approximately 15km/h (9mph) and is expected to weaken further over the next few days.

Severe Tropical Storm Jobo is forecast to make landfall over the eastern coast of Tanzania on 25^th April with maximum sustained winds speeds of 65km/h (40mph). The maximum storm surge height forecast for Tanzania is 0.2m. Jobo is expected to further weaken after making landfall and will dissipate after 27^th April.

Heavy rainfall and strong winds and storm surge are expected to affect Aldaba (Seychelles) Comoros, Mayotte and Tanzania.

Although cyclones making landfall in Tanzania are rare, they are not unheard of. On 15^th April 1952, a tropical cyclone (Lindi Cyclone) with wind speeds measuring 117km/h (110mph) made landfall in Lindi (Stephen M. Blumel, The Tanzania hurricane of 14-16 April 1952, National Weather Digest). This is equivalent to a Category 3 hurricane. Another cyclone called the Zanzibar cyclone made landfall over the island of Zanzibar on 14^th April 1872. Both cyclones had devastating impacts according to eyewitness accounts (Hellen E. Msemo, Declan L. Finney and Samwel I. Mbuya, Weather – Month 9999, Vol. 99, No. 99, Forgotten accounts of tropical cyclones making landfall in Tanzania).

Up to date information on Severe Tropical Storm Jobo can be found on the Joint Typhoon Warning Centre)

(References: GDAC, PDC, Joint Typhoon Warning Centre)

Track map of Jobo (Source: Joint Typhoon Warning Centre)

Satellite image of Jobo (Source: Joint Typhoon Warning Centre)

An insight into Dar es Salaam Floods and Flood Risk Management

Nearly every rainy season (March to May and October to November), Dar es Salaam, the commercial capital of Tanzania, experiences flooding. This year is no exception, with torrential down pours in May, flooding has already begun resulting in widespread damage to homes, businesses, road infrastructure and vehicles. 

According to the UNISDR Tanzania Disaster Risk Profile, floods affect an average 150,000 people (0.26% of the total population) in Tanzania. Floods are also responsible for an estimated average annual loss of $47 million (World Bank).

Recent studies and data has shown that the frequency and intensity of flooding in Dar es Salaam has increased due to intense rainfall as a result of climate change.

Both fluvial (river) and pluvial (surface water) flooding occurs in Dar es Salaam. The city has experienced a few significant flood events. Below are examples of recent significant events. 

December 2011 Floods:

Dar es Salaam experienced the worst flooding in December 2011, a T100 year event. The event witnessed the heaviest rainfall since Tanzania’s independence in 1961.

The floods resulted in 41 fatalities, injured over 200 people, displaced 10,000 people and affected an estimated 50,000 people. 2,500 people were reported to be missing. According to the Tanzania Red Cross, 680 temporary shelters were constructed to house 3,400 of the displaced. 

Widespread damage occurred throughout the city. The population living in the Msimbazi River basin were the worst affected. Homes were damaged, bridges destroyed and infrastructure including roads, were inundated causing disruption to the city’s transport.  

3,400 people were relocated as a result of these floods. The flood cost over TZS 1.8 billion.

Impact of the 2011 Floods (Source: The Msimbazi Opportunity Volume A)

Flooding at the Kawawa Road Bridge in 2011 (Source: The Msimbazi Opportunity Volume A)

April 2014 Floods:

Floods in April 2014 caused 19 fatalities, affected an estimated 20,000 people, washed away 13 houses in the Mzimbazi River Basin and inundated 600 houses. 283 people were treated for waterborne diseases such as cholera.

April 2018 Floods:

During the floods in April 2018, the Dar es Salaam Regional Commissioner declared a state of emergency. Evacuation was ordered for the population living in the high risk areas. 

The floods caused 15 fatalities, displaced 2,151 households, destroyed 42 houses and 21 latrines and severely damaged 342 houses according to the Tanzania Red Cross. Extensive damage was caused to road infrastructure and bridges. The city’s Bus Rapid Transit (BRT) system was also disrupted by the floods.

Jangwani Road flooded in 2016 (Source: The Msimbazi Opportunity Volume A)

Significant floods in Dar es Salaam between 1983 to 2006 (Source: World Bank Group: Promoting Green Urban  Development in African Cities Dares salaam, Tanzania Urban Environmental Profile)

Background and Challenges:

An estimated 6 million people live in Dar es Salaam and this is expected to increase to over 10 million by 2030, making it a megacity. 75% to 80% of Dar es Salaam’s population are estimated to live in unplanned areas, some of which are vulnerable to high flood risk.

Four main rivers run through the city including; Misimbazi, Mpiji, Kizinga and Mzinga. Msimbazi is the largest river and Kizinga has the largest catchment. 

Main areas at risk from flooding include the following:

• Msasani bonde la mpunga in the Kinondoni municipality
• Msimbazi valley
• Jangwani
• Mikoncheni
• Dar es Salaam city centre
• Kunduchi and Bahari beaches
  

With increasing population, rivers, in particular the Msimbazi River, have been degraded and polluted adding to the risk. The population of Dar es Salaam relay on these rivers for drinking, bathing and agriculture. 

Storm drainage systems which only cover the city centre are limited or inadequate, with 50% in poor condition. They are also unable to cope with the increasing rates of runoff caused by urbanisation. This leaves them unable to cope with the runoff, leading to flash floods. Other issues such as poor maintenance, siltation and waste disposal add to the challenge.

Deforestation, land and soil degradation and rapid urbanisation, are some of the issues increasing flood risk. Increasing densification of the population and building on the flood plain is resulting in exposure and vulnerability to floods. Infrastructure barriers, such as low bridges, are also adding to the problem.

According to the Msimbazi Opportunity Plan (discussed below), the main challenges linked to flood events are:

1.    Urbanisation and deforestation

2.    Soil erosion and increased sedimentation

3.    Infrastructure barriers

4.    Solid waste dumping

5.    Inadequate storm water and sanitation infrastructure

6.    Climate change effects

7.    Vulnerable living environments

Main rivers and tributaries in Dar es Salaam (Source: World Bank Group: Promoting Green Urban  Development in African Cities Dares salaam, Tanzania Urban Environmental Profile)

River catchment areas (Source: World Bank Group: Promoting Green Urban  Development in African Cities Dares salaam, Tanzania Urban Environmental Profile)

What is being done?

The Msimbazi Opportunity:

27% (2.1 million people) of Dar es Salaam’s population live in the Msimbazi Basin which covers 271 km². According to projections, 2.5 million people will be living in the Msimbazi Basin by 2030. 

Livelihoods, infrastructure and lives are at risk in this area, particularly in the Lower and Lower Middle Basin where the most severe flooding occurs after heavy rainfall. An estimated 8,000 to 10,000 households live in high risk areas which are unsuitable for human settlement.

Heavy rainfall results in flood depths of 2 metres or more in a matter of hours. It is not unusual to see peak discharge downstream within 3 hours, after rainfall. This short response time between rainfall event and flooding, gives those at risk little or no time to prepare and respond to the event. 

Residents are becoming more resilient and have adapted to regular floods by taking measures such as raising foundations, retaining walls, protecting property by moving them to the roof, placing sandbags, unblocking drains or as a last resort; temporarily migrating during floods.

Community resilience and response (Source: TURP 2018)

Extensive research and developments has been taking place in the Msimbazi Basin to understand and manage the flood risk. These include the development of digital elevation models (DEM) and numerical flood models, surveying using drones and satellites and urban mapping to capture buildings, infrastructure and assets using community mappers and data collectors. 

Research on the impact of soil erosion and river sedimentation on the flood dynamics, have been carried out on River Msimbazi and other main rivers in the city. Two studies have also been carried out to explore and quantify the relationship between poverty and flood risk in Dar es Salaam. 

You can find out more about these studies in the 2017 and 2018 Tanzania Urban Resilience Reports, linked in the reference section below.

Msimbazi river and tributaries (Source: World Bank Group: Promoting Green Urban  Development in African Cities Dares salaam, Tanzania Urban Environmental Profile)

The Msimbazi catchment area (Source: The Msimbazi Opportunity Volume A)

Msimbazi Charrette: meetings and workshops have taken place involving stakeholders including government officials, the private sector and the general public. These were organised to coordinate efforts in gathering an understanding of the vulnerability and risk from the recurring flooding and manage the flood risk. Over 150 representatives and 59 institutions were involved in 8 stakeholder workshops and 49 meetings which took place in less than 9 months. 1000 local residents have also been involved in the process.

The outcome of these Charrettes is the Msimbazi Opportunity Plan (MOP). The Msimbazi Strategy and Management Framework and detailed plan aim to ‘transform the Msimbazi Basin into a beacon of urban resilience’. The plan not only provides input into flood risk management, but also environmental protection and urban development for the Msimbazi Basin.

Some of the proposed solutions in the plan include:

• Dredging the river
•  Upstream reforestation to reduce erosion and sedimentation 
• Land use planning
• Transforming the high risk areas into wetland parks

Stakeholders have designed four strategies listed below to meet these solutions:

• Mitigate: reduce the flood hazard
• Protect: reduce the risk to people, properties and vital infrastructure 
• Transform: transform areas prone to flooding into a city park
• Govern: control, plan and coordinate development and ecosystem restoration to stop unplanned and uncontrolled urbanisation 

In addition to these strategies, 10 strategy components and 48 interventions provide the framework to see the implementation process through. The timeline to fully implement to framework varies from short term (2019 to 2023), medium term (2024 to 2031) and long term (2050).

The Mzimbazi Framework and Plans will be used as a template and example for other cities in Tanzania which face flooding.

You can find links to the full and detailed reports and plans in the reference section.

Flood extend map showing vulnerable infrastructure (Source: The Msimbazi Opportunity Volume A)

Example of a flood simulation model for Msimbazi. This map shows the flood depth at 60 hours of a T10 event (Source: The Msimbazi Opportunity Volume A)

Flood simulation model (Source: The Msimbazi Opportunity Volume B)

Proposed park to reduce flood risk in Msimbazi lower basin. (Source: The Msimbazi Opportunity Volume B)

Proposed park to reduce flood risk in Msimbazi lower basin (Source: The Msimbazi Opportunity Volume B)

Proposed wetland and city park to reduce flood risk in Msimbazi (Source: TURP 2018)

(Source: TURP 2018)

The Tanzania Urban Resilience Program:

The Tanzania Urban Resilience Program, also known as TURP, is a partnership between the Government of Tanzania, the World Bank Group and the UK Department for International Development (DFID). It is funded by DFID and aims to support the national and local government of Tanzania to manage urban climate risk. It was launched on 31 May 2017. TURBP supports the flood risk management efforts in the Msimbazi Basin.

‘A key objective of TURP is to support the introduction of modern methods for quantifying disaster risk, and the spectrum of potential impacts in order to build greater resilience into the urbanization process’.

The TURP has four pillars to work with:

1.    Risk Identification

2.    Risk Reduction

3.    Disaster Preparedness and Emergency Management

4.    Resilience Academy

TURP is providing support with designing early warning systems, improving flood monitoring and disaster risk management including emergency response plans and evacuation plans.

Dar es Salaam’s Multi-Agency Emergency Response Team (DarMAERT) with the support of the World Bank, have prepared a training, exercising and drills programs. The Emergency Operations Center and standard operating procedures have been reviewed and developed further.

The Rapid Transit Agency (DART) and Tanzania National Roads Agency (Tanroads), with the support of TURP, have been looking into contingency and emergency plans and developing a road map for short and long term emergency management to prepare for and reduce the impacts of disasters including flooding.

In October 2017, the DarMAERT Emergency Response Plan was launched. The plan provides a framework for emergency responders. It ensures that they know their role, are competent, work cooperatively with organisations and stakeholders and have access to resources and facilities required to respond to incidents.

A toolkit to support the creation of Community Disaster Response Plans at sub-ward level, is in the process of being prepared. The aim of these plan is to increase the community’s resilience by providing them with procedures on how to respond to flood events.

Figures:

• 26 km of flood zones have been mapped by UAVS
•  3 flood events have been captured
• 8 weather stations have been installed
• 4 community works shops on emergency management have taken place
• 4 radio base stations, 6 mobile stations and 3 repeater stations have been installed to assist with emergency response
• 6 training sessions on early warning systems have taken place
• Emergency communication has improved from 50% to 100% 

You can find links to the Tanzania Urban Resilience Program reports in the reference section.

Community Mapping:

The Ramani Huria (Open Mapping) project, is TURP’s community engagement and mapping project. It is based on community risk identification, data collection and socio-economic exposure mapping. 

Community mappers, including university students and community members, have been trained to identify community infrastructure and flood hazards and create sophisticated and accurate maps of Dar es Salaam.

Ramani Huria uses OpenStreetMap (HOT) which is an alternative and low cost method. They collect data on local infrastructure, drainage and household data. 

So far 20 wards at risk have been mapped at high resolution. Buildings, transport, drains, businesses and community assets have been mapped. They also collect input from communities at risk regarding flood inundation and flood impacts.

Meetings have been conducted by the team with different actors in the community to discuss assets at risk and possible threats perceived by the community at sub-ward level. The team have also started creating community risk maps.

Some of the achievements of the Ramani Huria Project:

• 350 Tanzanian students have been trained across 22 institutions
• 35,000 households have taken part to collect community knowledge
• Over 960 citizens have been trained with basic mapping skills using locally accessible tools in the 2018 financial year
• 44 wards have been mapped
• 1254 km of waterway have been mapped
• 3396 km of roads have been mapped

The data collected intended to support inundation modelling, exposure mapping, and land use planning.

The project is currently ongoing. You can find out more about them on their website.

The video below provides information on the project.

Videos:

Follow this link to watch a video by the World Bank on the Msimbazi River and its role on urban floods: Video on The Msimbazi River and its Role on Urban Floods

2018 Flood Impacts:

References:

• CIMA, UNISDR (2018). United Republic of Tanzania Disaster Risk Profile
• Reliefweb
• Tanzania Red Cross Society
• Tanzania Red Cross Society: Emergency Plan of Action
• World Bank: Promoting Green Urban Development in African Cities Dar es Salaam, Tanzania Urban Environmental Profile, 2016
• Kebede, A. and Robert Nicholls, 2010. Population and Assets Exposure to Coastal Flooding in Dar es Salaam (Tanzania):   Vulnerability to Climate Extremes. Report Submitted to Global Climate Adaptation Partnership. January 2011
• World Bank and DFid, Tanzania Urban Resilience Programme (TURP), Annual Report 2018.
• World Bank and DFid, Tanzania Urban Resilience Programme (TURP), Annual Report 2017.
• Ramani Huria
• The Msimbazi Opportunity, Transforming the Msimbazi Basin into a Beacon of Urban Resilience, Executive Summary, 29 January 2019
• The Msimbazi Opportunity, Transforming the Msimbazi Basin into a Beacon of Urban Resilience, Volume A:Strategy and Management Framework
• The Msimbazi Opportunity, Transforming the Msimbazi Basin into a Beacon of Urban Resilience, Volume B:Detailed Plan for the Lower Basin
• The Msimbazi Opportunity, Transforming the Msimbazi Basin into a Beacon of Urban Resilience, Volume C:Appendices
• The Msimbazi River and its Role on Urban Floods
• Tanzania Urban Resilience Program