Research on intense precipitation could increase preparedness upon local flooding

In recent times, abundant rainfall over southwestern Sweden has caused high water levels and flooding. An ongoing research project is developing flow forecasts which are better at capturing the effects of sudden downpours. It allows for better preparedness upon local, extreme water flows in the future. 

Intense precipitation, in the form of, for example, heavy rainfall, may cause very high water and flooding at a local level. Especially vulnerable are cities and areas that are bare and steep. Today, there is no system to warn of floods caused by extreme rainfall.

- We need better descriptions of how powerful bursts rapidly affect the flow process. Especially because of the fact that extreme rainfall may increase in the future due to a warmer climate, says Jonas Olsson, researcher in hydrology at SMHI.

A tool with more detailed information may provide a better basis for assessing the risk of extreme water flows.

- We work with using radar observations in combination with station data and we evaluate and test how to use more detailed precipitation forecasts, says Jonas Olsson. We also adjust the receiving system called S-HYPE, which is used to make hydrological predictions, so that it is possible to forecast with short time intervals.

More frequent flow forecasts

Today, the flow forecasting time interval is one day. In the future, the goal is to reduce the time interval to e.g. 3 or 6 hours.

- To make detailed forecasts with short time intervals, however, requires very large computing capacity.

The long-term goal is to upgrade the national system for denser flow forecasts. This would greatly improve the ability to predict and describe the rapid and local high flows and flood risks.

The project is funded by the MSB, the Swedish Civil Contingencies Agency, and runs from 2012 to 2015. Besides SMHI, the Swedish Geotechnical Institute (SGI) and Karlstad University are included in the project organisation.