The influence of antecedent conditions on flood risk in sub-Saharan Africa
Most flood early warning systems have predominantly focused on forecasting floods with lead times of hours or days. However, physical processes during longer timescales can also contribute to flood generation. In this study, we follow a pragmatic approach to analyse the hydro-meteorological pre-...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-01-01
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| Series: | Natural Hazards and Earth System Sciences |
| Online Access: | https://www.nat-hazards-earth-syst-sci.net/18/271/2018/nhess-18-271-2018.pdf |
| Summary: | Most flood early warning systems have predominantly
focused on forecasting floods with lead times of hours or days. However,
physical processes during longer timescales can also contribute to flood
generation. In this study, we follow a pragmatic approach to analyse the
hydro-meteorological pre-conditions of 501 historical damaging floods from
1980 to 2010 in sub-Saharan Africa. These are separated into (a) weather
timescale (0–6 days) and (b) seasonal timescale conditions (up to 6 months)
before the event. The 7-day precipitation preceding a flood event (PRE7) and
the standardized precipitation evapotranspiration index (SPEI) are analysed
for the two timescale domains, respectively. Results indicate that high
PRE7 does not always generate floods by itself. Seasonal SPEIs, which are
not directly correlated with PRE7, exhibit positive (wet) values prior to
most flood events across different averaging times, indicating
a relationship with flooding. This paper provides evidence that bringing
together weather and seasonal conditions can lead to improved flood risk
preparedness. |
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| ISSN: | 1561-8633 1684-9981 |