Meteorological causes of flooding

• The likelihood of flooding is increased by other physical circumstances

  • in low-lying areas with impervious surfaces, as in towns and cities
  • where the ground surface is underlain by impermeable rocks
  • when ice dams suddenly melt and the waters in glacial lakes are released
  • where volcanic activity generates meltwater beneath ice sheets that is suddenly released (jökulhlaups)
  • where earthquakes cause the failure of dams or landslides that block rivers
• Tidal flooding

  Often a result of storm surges or when high river flows meet particularly high spring tides in estuaries. A storm surge is caused by very low air pressure which raises the height of the high-tide sea. Strong onshore winds then drive the 'raised' sea towards the coast, often breaching coastal defences and flooding large areas.
• Bangladesh

  Bangladesh is a particularly food-prone country mainly because it is a land of floodplains and deltas built up by mighty rivers such as the Ganges, Padma and Meghna. These rivers are swollen twice a year by meltwater from the Himalayas. and by the summer monsoon. Hilly tracts between the rivers and behind Chittagong are often victims of flash floods.