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Precipitation and temperature

Maps and description of the daily precipitation and the daily mean temperature during the events. The daily data are also available for download as NetCDF files.


Daily precipitation

Between 24 and 27 July 2014, precipitation did not fall continuously over one region but affected different regions depending on the day. This highlights the local nature of the thunderstorms, which can occur over any region depending on the heating of the ground by the sun. Hence, the Emmental and Entlebuch regions were not the only regions in Switzerland to receive precipitation and sometime larger rainfall amounts were measured in other areas. By and large, the thunderstorms that occurred during that time span affected places with rough topography, namely the Prealps, the Jura and the Alps.

On 24 July, thunderstorms occurred along the Prealps and the Alps, with a precipitation hotspot located over the upper Emmental, over which 50 to 140 mm of rain were measured by the radars between 24 and 25 July, 00 UTC (see radar image below). No measurement station exists in that region, however, station Schwarzenegg located nearby in the region of Thun recorded 30.5 mm of rain that day. In the rest of Switzerland, relatively high daily precipitation was also measured in the Prealps (e.g. Le Moléson FR, 23.2 mm), in the Alps (e.g. Klöntal GL, 24.2 mm), as well as on the Plateau (Lausanne VD, 26.9 mm).

On 25 July, the Emmental/Entlebuch region received less precipitation and, that day, higher rainfall took place over the Jura chain (e.g. Les Brenets NE, 50.8 mm; La Cure VD, 49.8 mm).

On 26 July, thunderstorms again affected the upper Emmental, as well as the upper Entlebuch. For example, 37.7 mm of rain were measured at station Marbach, 35.3 mm at station Schüpfheim and 24 mm at station Schwarzenegg. That day, larger rainfall amounts were also measured in the Alpstein (e.g. Schwägalp, 78.4 mm), in the Rheintal (e.g. Widnau, 69.8 mm) and in central Switzerland (e.g. Alpthal SZ, 66.4 mm).The latter regions, located in the eastern part of Switzerland, received again precipitation on 27 July (e.g. Schwägalp, 29.4 mm).

The nature of the precipitation changed on 28 July, being then related to the passage of a cold front over Switzerland instead of local convection. This resulted in the rainfall being spread over a larger area (Prealps, as well as the northern and southern side of the Alps) and in the occurrence of larger rainfall amounts. Again, the Emmental/Entlebuch region received high precipitation (e.g. Luthern, 78 mm ; Napf, 71.4 mm ; Kurzeneialp, 64.7 mm ; Schüpfheim, 58.6 mm). That day, larger daily precipitation amounts were also measured in the Canton of Obwald (Giswil, 79.4 mm), as well as in Ticino (Brissago, 93.4 mm; Sigrino, 84.8 mm; Càmedo, 71.8 mm).

For the stations located in the Emmental/Entlebuch region, the maximum daily precipitation measured between 24 and 28 July corresponds to one fifth to one half of the normal monthly July precipitation for those stations (norm 1981-2010). Even though for most stations the daily precipitation amounts are not extraordinarily high (see section Extreme value analysis), what made these events particularly damaging is the fact that most of the rain fell over a time lapse of only a few hours, leading to high surface runoff (see section Hyetographs).

Daily mean temperature

During these events, temperatures in the Emmental and Entlebuch regions were relatively high, with daily mean temperatures between 6 and 20°C, causing the precipitation to fall in a liquid form.


RhiresD is the spatial analysis of daily precipitation in Switzerland. The daily precipitation on day D corresponds to the rainfall and snowfall water equivalent accumulated from 06:00 UTC of day D to 06:00 UTC of day D+1. For more information about this data set, see the documentation given below.

TabsD is the spatial analysis of the daily mean air temperature 2m above ground level and is representative of the average from midnight to midnight UTC. For more information about this data set, see the documentation given below.