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Abstract. Derechos are high-impact convective wind events that can cause fatalities and widespread losses. In this study, 40 derechos affecting Germany between 1997 and 2014 are analyzed to estimate the derecho risk. Similar to the United States, Germany is affected by two derecho types. The first, called warm-season-type derechos, form in strong southwesterly 500 hPa flow downstream of western European troughs and account for 22 of the 40 derechos. They have a peak occurrence in June and July. Warm-season-type derechos frequently start in the afternoon and move either eastward along the Alpine forelands or northeastward across southern central Germany. Associated proximity soundings indicate strong 0–6 and 0–3 km vertical wind shear and a median of mixed-layer convective available potential energy (mixed-layer CAPE) around 500 J kg−1. The second derecho type, the cold-season-type derecho, forms in strong northwesterly 500 hPa flow, frequently in association with mid-tropospheric potential vorticity (PV) intrusions, and accounts for 18 of the 40 derechos. They are associated with a secondary peak from December to February. Cold-season-type derechos start over or close to the North Sea and primarily affect northern and central Germany; their start time is not strongly related to the peak of diurnal heating. Proximity soundings indicate high-shear–low-CAPE environments. A total of 15 warm-season-type and 9 cold-season-type derechos had wind gusts reaching 33 m s−1 in at least three locations. Although warm-season derechos are more frequent, the path length of cold-season-type derechos is on average 1.4 times longer. Thus, these two types of German derechos are likely to have similar impacts.

Abstract. Derechos are high-impact convective wind events that can cause fatalities and widespread losses. In this study, 40 derechos affecting Germany between 1997 and 2014 are analysed to estimate the derecho risk. Similar to the United States, Germany is affected by two derecho types. The first derecho type forms in south-westerly 500-hPa flow downstream of intense west-European troughs and accounts for 22 of the 40 derechos. These derechos are named warm-season type due to their peak occurrence in June and July. Warm-season type derechos frequently start over southwestern Germany in the afternoon and move either eastward along the Alpine forelands or north-eastward across southern central Germany. Only one warm-season derecho moved across the North Sea and one moved across the Baltic Sea in the 18-year period. Proximity soundings of German warm-season type derechos indicate strong deep-layer vertical wind shear with a median of 20 m s−1 0–6-km shear and mixed-layer Convective Available Potential Energy (mixed-layer CAPE) between 20 and 2600 J kg−1 with a median around 500 J kg−1. The second derecho type forms in north-westerly 500-hPa flow and accounts for 18 of the 40 derechos. These derechos form in strong north-westerly flow, frequently in association with mid-tropospheric PV intrusions. They are named cold-season type because they are associated with a secondary peak from December to February. Cold-season type derechos start over or close to the North Sea and primarily affect north and central Germany; their start time is not strongly related to the peak of diurnal heating. Proximity soundings indicate high-shear–low-CAPE environments with a median 0–6-km shear of 35 m s−1 and a median mixed-layer CAPE of 3 J kg−1. Environmental CAPE is zero in almost half of cold-season type proximity soundings. Fifteen warm-season type and nine cold-season type derechos had wind gusts reaching 33 m s−1 in at least at three locations. Although warm-season derechos are more frequent, the path length of cold-season type derechos is on average 1.4 times longer. Thus, these two types of German derechos are likely to have similar impacts.