KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
EF3 rain-wrapped tornado embedded in a
macroburst in Côte-d’Or (NE France)
on June 19, 2013
An EF3 tornado hit the northern part of Côte-d’Or on June 19, 2013, around 5:40 p.m. local (1540z).
This is the strongest tornado recorded in France since the EF4 tornado of Hautmont, in August 3,
2008.
The identification of this tornado required an extensive damage survey. Indeed, it was associated
with a large macroburst, composed of about thirty microbursts.
The affected area extends over 11.000 hectares, which required 3 days of investigation for the
KERAUNOS team.
Following these analyses, it appeared that the multitude of nontornadic damage identified on the area is organized on both
sides of a corridor of damage which is caused by a strong
tornado.
►
Key features of the tornado
Maximum intensity : EF3 (winds from 220 to 270 km/h)
Distance path : 14 km
Average width : 250 meters
Townships impacted : POINCON-LES-LARREY, BOUIX,
ETROCHEY, MONTLIOT-ET-COURCELLES, MASSINGY
Department : COTE D'OR (21)
Mean ground elevation : 230 meters
Land type : agricultural land, grasslands, discontinuous urban landscape
►A
tornado embedded in a macroburst
Investigations were carried out by Keraunos to determine the exact nature of the phenomenon.
The main damage area covers more than 10,000 hectares. Undoubtedly, a powerful macroburst
caused diffuse and sometimes significant damage in this area: uprooted or broken trees, damaged
roofs; etc.. The damage area has a 3 to 10 km large front, with a depth of 18 km.
However, a well defined corridor of damage was gradually revealed between Etrochey and Montliotet-Courcelles, and between southern Poinçon-lès-Larrey and Massingy. This corridor appeared in the
southern portion of the region devastated by the macroburst, and is well isolated from the other
damage.
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
The presence of a strong convergence in the surface flow in this corridor confirms a tornado
occurrence in this area. The path followed by the tornado is marked by a furrow in the fields
between Etrochey and Montliot-et-Courcelles.
The tornado, with a total path of 14 km, has thus moved from southwest to northeast, with some
deviations. Locally in the Etrochey area, the maximum width of the tornado path is about 400 meters
large.
Blue: macroburst damages - Red: tornado damages
Minor macroburst damages are not all included for readability
This is the only recent tornado case in France which occurred with a macroburst. This gives it a real
originality.
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
Analysis of the tornado intensity
While most of the damage is in the EF1 and EF2 range (roof removed, broken trees, little projectiles),
several indices of an EF3 intensity appear in two distinct locations :
1: in the Etrochey area
- farmhouse (built in stone) completely demolished,
- concrete poles cut halfway or broken at the base,
- several mature hardwood trees debarked,
- tiles thrown 500 meters away from their initial location.
2: in the Montliot-et-Courcelles area
In the immediate vicinity of a house whose roof and gable wall is completely torn, a stone (1 ton) is
moved a few meters. Not far away, iron bars firmly attached were lifted up and planted deep in the
ground, 70 meters away from their original location. Finally, the debris from the roof of the damaged
home, and the entire cottage garden attached, were found several hundred meters away in a field.
Tornado path
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
Photography of the damage
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
(C) LE BIEN PUBLIC
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
Radar imagery and supercell organisation
It appears that the tornado formed in a supercell, which formed about an hour earlier, around 4:45
p.m., at the border between Yonne and Côte-d'Or. Soon the storm cell grew and moved to the right
of the average flow.
At 17:10 pm. the supercell entered the territory of Côte-d'Or and rapidly moved towards the area of
Châtillon-sur-Seine. The forward flank downdraft (FFD) reinforced its activity quite quickly, followed
shortly after, around 17:30, by a strengthening of the rear flank downdraft activity. It seems that the
supercell initiated an HP phase.
The, the tornado formed about 5:40 p.m. to 5:45
p.m.. The radar image below, provided by courtesy
of Meteo Swiss, allows to identify a powerful rear
flank downdraft (RFD). The tornado (T) is likely
localised on the northwest side of the RFD. The RFD
itself generates a first axis of strong winds, heavy
rain and 4 cm large hailstones.
Just to the north, the front flank downdraft (FFD) is
also very active and also generates severe wind
gusts.
So, the whole supercell generates a first macroburst
related to the FFD, which runs north of the tornado,
and a second macroburst related to the RFD which
runs from the west of the tornado to its southern
flank.
Due to this organisation, which is typical of an HP supercell, the tornado was preceded and followed
by intense rainfall and hail, surrounded by violent downbursts, and wrapped by rain.
Analysis of the meteorological situation
A cut-off low is in position between the Bay of Biscay and southwestern France for several days.
During the afternoon of June, 19, the situation becomes much more dynamic on northeastern
France, thanks to the combined effect of an increase of mid-level relative vorticity and high-level
diffluence caused by a right-entrance of a jet-streak moving towards northwestern France.
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
A reconstructed profile has been realized on the basis of surface weather data from the weather
station of Châtillon-sur-Seine (located a few kilometers to the south of the tornado path), on
reanalysis data and WRF model. This profile shows a MUCAPE > 5000 J/kg, a MLCAPE > 2851 J/kg and
a MULI < -13K. MLLI has reached -10K at 9000 m in the WRF simulation. These values reflect the
extreme instability of the air mass on this 19 June.
The dew point of 23°C recorded in Dijon and Chatillon-sur-Seine during the afternoon confirmed the
high humidity of the air mass.
MUCAPE and MLCAPE (WRF 16 km)
In the same time, the environment was characterized by significant deep shear (more than 20 m/s)
and by significant low-level helicity (0-3 km SRH of 239 m²/s²), which is favorable for supercell
storms.
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version
KERAUNOS
Tornadoes and Severe Storms French Observatory
Website : www.keraunos.org
KERAUNOS – EF3 tornado in Cote-d’Or / France – June 2013 / English version