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29 Apr 2024 | 02:35 PM UTC

Madagascar: Adverse weather forecast across eastern and northern regions through at least May 3

Severe weather forecast across eastern and northern Madagascar through at least May 3. Flooding and associated disruptions possible.

Warning

Severe weather is forecast across parts of eastern and northern Madagascar through at least May 3. Heavy rainfall accompanied by thunderstorms is expected across the affected area over the coming days. Daily rainfall totals of 4-9 cm (1.6-3.5 inches) are likely across the region, with the heaviest rainfall likely in parts of Atsinanana Region April 29-May 1, across Ambatosoa, Analjorofo, northern Atsinanana, and Sava April 29-May 2, and Diana and Sofia regions May 1-3. The heavy downpours may trigger flooding, rising river levels, and landslides in the region. Strong winds may cause property damage and power outages.

As of April 29, the Madagascar General Directorate of Meteorology has issued the following warnings across the affected area:

  • Red heavy rainfall warnings (the highest level on a three-tier scale): Ambatosoa, Analjorofo, Atsinanana, and Sava regions.
  • Green heavy rainfall warnings: Diana and Sofia regions.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil. Disruptions to electricity and telecommunications services are possible where significant flooding, strong winds, or landslides impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at airports in the affected regions. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities and some employees' inability to reach work sites.

Flooding could heighten the threat of disease outbreaks. Backflow from drains mixed with floodwaters can become trapped in open areas when inundations recede. These stagnant pools often become breeding grounds for mosquitoes and bacteria, increasing the incidence of insect- and water-borne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.

Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Observe strict food and water precautions, as municipalities could issue boil water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming days. Charge battery-powered devices in the case of prolonged electricity outages.