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Only a few days after Medicane TRUDY the low HEINER again provided heavy rain and snowfall in Italy, Austria and Croatia. In Italy a record flood of
160cm was registered in Venice for the second time in a row. In South and East Tyrol 160cm of fresh snow came together and gusts of 130 kph were registered.
Weather situation and development
As soon as Medicane TRUDY had left (see Medicane TRUDY ), the low HEINER set course for Italy and the Alps. It developed on Friday Nov 16 over Africa at the top of the pronounced
trough over Europe. In the course of the day it came to the frontside of the trough and quickly shifted to the northeast, crossing the Mediterranean/Tyrrhenian Sea.
There it gained in intensity, because it got into an area of favorable environmental conditions. HEINER was located in the area of a left jet exit and a right jet
entrance. However, it did not develop into a medicane, as the water temperatures were much too low (SST 18-20 degrees). Nevertheless, it was able to refuel a lot
of water vapour until it reached central Italy on the morning of Nov 17. In the course of the day it quickly shifted to the north and reached the southeast of
Germany in the evening and began to weaken.
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Sea level pressure and fronts, November 14-17, 2019:
FU-Berlin
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The enormous amounts of precipitation mainly came together on Saturday and Sunday in the Alpine regions, favoured by positive vorticity advection in 500 hPa
height and layer thicknesses advection. The southwesterly wind pushed the humid air masses against the coasts and the Alps, which act as a barrier.
Accumulated precipitation occurred mainly in the south and east of Austria. Almost 140mm came together in 24 hours (see table below). At lower altitudes these
fell as rain, at higher altitudes as snow, resulting in floods and enormous amounts of fresh snow. Furthermore, the high air pressure gradient in Austria caused
widespread gale gusts and hurricane force like winds, resulting in a snow storm.
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Satellite images (visible), November 10-13, 2019:
Sat24
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Italy, especially the areas on the Adriatic coast, still had to struggle with the Medicane TRUDY flood. Already at this time a state of emergency was declared.
There were already floods on Nov 12 by severe precipitation and storm surges and high tides. A similar situation arose due to deep HEINRICH. Strong winds caused
high waves in addition to the precipitation. In Venice there was another record flood, as well as in other parts of Italy and Croatia. In Croatia there was the
danger of hurricane like winds near the coast as well as thunderstorms.
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500 hPa Gopotential, November 14-17, Source:
Wetter3
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Sea level pressure and precipitation, November 17-18, Source:
Wetter3
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Observations and Damages
Austria had to struggle with floods and enormous amounts of fresh snow. This led to states of emergency and disaster areas were declared. The exact number of
death victims is not known yet. Due to the floods and snowfalls, buildings were evacuated, schools and kindergartens are expected to remain closed until Wednesday
Nov 20. In the affected ski and holiday areas, the pistes and hiking trails were closed. In Villach the level of Lake Faak rose from 40cm to 140cm. Statistically
this only happens every 100 years.
In Tyrol and East Tyrol up to 180cm of fresh snow fell. This increased the danger of avalanches enormously. Already days before it had rained heavily
(24mm in 24 hours, locally also higher), which soaked and washed out the ground. This favoured avalanches not only on steep slopes, but also on slopes with
low inclination.
The snowfall was accompanied by hurricane force like winds and eventually turned into a snow storm. There were power outages and blocked roads, even in alpine
valleys. The avalanches damaged many houses and made roads impassable. Whole villages were cut off from the outside world. There is also a danger of snow and mud
avalanches in the coming days. The danger of falling trees and breaking branches is still high because the weight of the new snow is too great. New severeweather
have already been announced for Tuesday Nov 19.
In Italy and Croatia the people had to struggle with flooding, especially Venice. A state of emergency had already been declared there days before due to the
Medicane TRUDY. Even on Nov 18 the water was still 160 cm high, but it quickly drained off in the afternoon. As a result, a record flood water level was reached for
the second time in 50 years this week. The last time the value of 160cm was reached was in 1966. Normally floods reach a height of 80-90cm. The buildings are
permanently damaged by the salt water, but also by the frescoes and other murals. San Marco Square remained closed, as did many other buildings.
The Canal Grande crossed its banks and the boat traffic was partly stopped. An estimated 1.1 billion dollars of damage occurred this weekend alone.
Other areas in Italy also experienced severe floodings, with the river Arno in Pisa threatening to burst it banks.
In the table below you can see 24 hours precipitation in Austria (left) and Gusts (right), below the precipitation for Italy and Croatia:
| Location |
Precipitation amount in mm |
Date |
Kötschach/ Manthen
Mallitz Ii
Dellach im Drautal
Lienz
Rauris
Sillian
Weissensee/ Gatschach
Zell am See
Virgen
Maria Alm
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137.6
134.6
126.5
117.1
111.8
103.8
94.2
82.6
80.8
80.6
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17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
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| Location |
Gusts in kph |
Date |
Brunnenkogel
Sonnblick
Villacher Alpe
Feuerkogel
Loferer Alm
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130
130
126
122
108
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17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
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| Location |
Precipitation amount in mm |
Date |
Zavizan (CR)
Rijeka/Omisalj (CR)
Bologna/Bogo Panigale (IT)
Bologna (IT)
Firenze (IT)
Napoli/Capodichino (IT)
Grosseto (IT)
Knin (CR)
Puntijarka (CR)
Zagreb/ Gric (CR)
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125.0
113.9
107.6
85.0
84.0
70.0
60.0
56.0
55.0
49.0
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16.11.2019
16.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
17.11.2019
16.11.2019
16.11.2019
16.11.2019
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Data source: Ogimet.
Text: MG
November 18, 2019
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