Africa: Annual rainy season to occur across parts of northern regions through April /update 1

Event

Sustained heavy rainfall conducive to flooding and landslides is possible across most of North Africa, including Algeria, Tunisia, Morocco, and Libya, in the coming months amid the region's primary rainfall season, which occurs October-April. Heavy downpours, flooding, and landslides could affect business, transport, and utility services in many areas. Meteorological agencies throughout northern Africa could issue weather warnings in response to the upcoming rainy season, particularly if extreme rainfall, severe thunderstorms, or strong winds are forecast.

This risk of flooding is highest in low-lying communities near watercourses in recognized floodplains. North Africa has several major rivers, including the Bou Regreg, Chelif, Draa, Moulouya, and Oum Er-Rbia, which could flood during periods of intense rainfall. Flash floods can occur with little to no warning and often threaten communities downstream of major rivers or dams in the event of infrastructure failure. Even relatively low amounts of precipitation can trigger flood events in areas where dry, compacted soil is unable to absorb runoff. Storm surges may trigger flooding in coastal areas. Landslides and mudslides are possible in hilly and mountainous regions including the Atlas Mountains in Morocco, Algeria, and Tunisia. Localized disruptions could persist well after hazardous events have concluded; floodwaters may take days to subside, and clearance of resulting mudslide debris could take weeks.

Communities with poor or a lack of stormwater drainage systems may experience urban flooding during periods of significant rainfall, while areal flooding poses a threat to sites near rivers and streams - particularly those within recognized floodplains. Rural communities and informal settlements often suffer the most significant damage and casualties during such events due to poor infrastructure.

Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas, especially in rural areas, where infrastructure is already of a poor standard. 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 domestic and international airports. Authorities may temporarily suspend port operations or close beaches if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation. Delays to rail transport are also possible, especially for shipments along railway systems near the edge of area watercourses; floating debris and inundated tracks could lead to service suspensions.

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

Health
The threat of disease outbreaks is elevated during the rainy season. Backflow from drains that has mixed with floodwaters can become trapped in open areas when inundations recede. These stagnant pools often become a breeding ground for mosquitoes and bacteria, increasing the incidence of insect- and waterborne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.

Advice

Monitor local media for updates and advisories on weather conditions. Confirm all transport reservations (air, ground, and maritime) prior to travel. Make allowances for possible supply chain disruptions throughout the rainy season, particularly in areas affected by flooding and or/landslide events.

Avoid low-lying areas near streams, rivers, and other bodies of water, such as reservoirs and coastlines, due to the threat of flooding. Do not drive on flooded roads. Exercise caution in elevated terrain due to the threat of landslides and mudslides. Charge battery-powered devices when electricity is available; restrict the use of cellphones to emergencies only during periods of severe weather. Take precautions against insect- and waterborne diseases. Keep any necessary medications in a waterproof container

Resources

Algeria Office National de la Meteorlogie
Tunisia National Institute of Meteorology
Morocco Direction de la Meteorologie Nationale