Continued risk of flooding
Just a glance at the region around the small Greifensee lake in Zurich's Glattal valley shows that the flood situation in Switzerland has not yet eased.
Today, Friday, shower and thunderstorm activity from the southwest will increase again in the second half of the day. Rain is to be expected repeatedly until Sunday morning. MeteoSwiss expects the most precipitation between Friday noon and Saturday noon along the central and eastern foothills of the Alps as well as in the adjacent Central Plateau. In the mentioned areas, 20 liters per square meter can be expected. Locally, 35 liters are possible within a short time. On the remaining northern slopes of the Alps and in the Jura, 10 to 20 liters per square meter are expected to fall, in the remaining lowlands around 5 to 10 liters.
Thanks to the break in precipitation over the past few days, the water levels of the watercourses have fallen and are currently mostly in the danger level 1 range, with the exception of the lake outlets, in particular of Lake Thun and Lake Biel. In the case of the lakes bordering the Jura, water from Lakes Murten and Neuchâtel will flow into Lake Biel as soon as the level of Lake Biel falls below that of Lake Neuchâtel. In order to provide greater relief for the Jura lakes, the outflow from Lake Biel is regulated at a very high level in agreement between the federal government and the cantons. The authorities expect that it will take a long time (several weeks) until normality is reached.
The flood hazard on Lakes Neuchâtel and Biel and on the Aare below Lake Biel remains very high (level 4). On Lakes Thun and Murten and on the Aare below Lake Thun, it remains high (level 3).
The predicted precipitation until Sunday, May 10, may lead to a local increase in discharges, especially in small and medium-sized watercourses. Should the Emme catchment area be affected by the precipitation, the discharge at the Port weir would have to be throttled again immediately. In this case, the level of Lake Biel would quickly rise sharply.
In the vicinity of rivers and lakes with high water, the greatest caution is advised, as it is stated on the Natural Hazards Portal means. The instructions of the local authorities must be followed.
Incidentally, risk management of natural hazards is presented on the occasion of a Special show at the SECURITY 2015 (November 10 - 13). The trade show will be accompanied by a congress: in June 2015, the detailed Program.
