The exceptional rainfall episode registered in Lisbon in 18 February 2008

Fragoso M., Trigo R.M., Zęzere L., Valente M.A.
Weather, 65, 31-35

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On 18 February 2008, the Lisbon city district, in the capital of Portugal, suffered the rainiest day on record since the continuous daily precipitation data at the D. Luís Observatory was first published in 1864 in the Observatory's log books (Annales). On this day, 118.4 millimetres was recorded at the Observatory, exceeding the previous highest daily total recorded as long ago as 1876. This extreme event was responsible for a wide variety of negative impacts, namely urban inundations (motivating hundreds of calls to the fire-fighters and civil protection brigades), flash flooding (occurring mostly in small drainage basins with short concentration times, such as the one shown in Figure 2), and landslides (a total of 64 occurrences related to slope instability were reported). The National Authority of Civil Protection reported four deaths, 65 people dislodged and 121 evacuated in safety and rescue operations. No official information is available concerning the estimate of total financial costs associated with this extreme event, considering that other direct and indirect impacts of the storm should be taken into consideration: namely those associated with disruption of train services, blocked roads and electric power breakdowns. In this paper, we study the spatial distribution and temporal evolution of this extreme rainfall event. Then we fit an appropriate extreme values distribution and compute the return period associated with this event for several stations available in the Lisbon area. Finally, we provide a short description of the evolution of the synoptic situation leading to this extreme rainstorm.