thunderstorm systems were formed over the ocean near to the western coast of Portugal and moved slowly towards the Lisbon region throughout the night, between the late hours of 17 February and the early hours of 18 February. By the time those convective cells reached the Lisbon area, deep cloud systems had moved and passed slowly over the study area for more than eight hours, being responsible for intense precipitation activity that resulted in accumulated values exceeding 100 millimetres.The effects of the storm in the Lisbon metropolitan region were harmful and in some cases even ruinous. A large number of urban inundations and country flash-floods have caused loss of life and serious damage to property, demonstrating some lack of preparedness on the part of the city to respond suitably to these natural hazards and risks. These facts show the importance of studying with more detail the impacts and consequences of an extreme rainstorm in Lisbon, in order to prevent future disasters and to propose suitable mitigation measures. References