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temperature (the steeper and the most significant one among the
seasons) in Hungary is ca. 1.0 degrees Celsius for 1901-2006.
Under the climate of Hungary, summer heat waves occur
rather frequently, hence an operative heat alarm system has
been in use since 2004. According to the Hungarian heat alarm
experience, if the daily mean exceeds 25 degrees Celsius on at
least three consecutive days, the medical risk rises by 15 per
cent. If the daily mean is above 27 degrees Celsius for at least
three consecutive days, the increase in risk is 30 per cent.
According to the definition of heat alarm levels, the HMS
issues a warning signal for the National Ambulance Service
and the National Public Health Service. The warning signal is
also appears on the Web site of the HMS according to the
regions of the country. The actual extreme weather conditions
are analysed on the Web site of the HMS to inform the public.
According to climate statistics, the occurrence of hot periods
with 25 degrees Celsius average temperature grew by around
six days, trend estimation suggests. Heat waves with over 27
degrees Celsius temperature exhibited a three-day increase
during the 1901-2006 period.
Flash floods
Monitoring of flash floods depends on population density, due
to the small coverage of such phenomena. Chronicles usually
mention them in connection with large damages. Therefore,
we know about many flash flood events in Hungary from the
Middle Ages.
Preliminary studies concerning regional climate changes indi-
cate that, besides the more frequent drought events in Hungary,
short-term precipitation intensity is also increasingly likely,
according to the finer resolution models and empirical analyses.
Several flash floods have occurred in Hungary in the recent
years. For example, experts from the Disaster Management
Directorate of Nograd County (northern Hungary), one of the
19 counties of Hungary with an area of 2,540 square kilome-
tres, noted five flash floods in 2004, seven in 2005, and six in
2006. Altogether, more than 400 houses were damaged in the
small villages among the hills and around 600 people became
temporarily homeless. The total damage of these events was
in the region of EUR2 million.
HMS experts in radar meteorology have a calibrated precip-
itation archive extending more than ten years, where 15 minute
0
50
100
150
200
250
1955
1965
1975
1985
1995
2005
Precipitation
April precipitation sums since 1953 at Mátraszentlászló, Hungary. The dashed line shows the precipitation sum that occurred in
two hours on 18 April 2005
Source: OMSZ
area means are prepared in 2x2 km resolution. These maps are
used in two ways. In the given case they contribute to docu-
mentation and re-compensation of damages. More generally,
they provide good guidance for local governments to elabo-
rate flexible warning systems in anticipation of further events,
including proactive measures to mitigate damages.
A large flash flood devastated Mátrakeresztes on 18 April
2005. The nearby precipitation gauge (Mátraszentlászló)
measured 111 millimetres in two hours. Simultaneously, hail
rained down for about 40-50 minutes. Precipitation during
these two hours was higher than the monthly averages even
during the wet months, before 2005.
Windstorms
Severe storms are not unusual in the Carpathian basin. They
are mostly connected with intense extratropical cyclone activ-
ity. Windstorms in Hungary partly occur in winter and are
recorded in a very severe cyclone, a so-called cyclonic bomb.
Summer storms are consequences of intense convection in the
atmosphere. Fast running cold fronts, squall lines and thun-
derstorm supercells can generate heavy storms with gusts
stronger than 30 m/s (108 km/h). The highest wind gusts in
Hungary are ranked as follows: Szarvas (southeast Hungary),
3 August 1988: 44.5 m/s (160.2 km/h); Szeged (south
Hungary), 12 July 1993: 44.3 m/s (159.5 km/h) and Sopron
(west Hungary), 15 February 1990: 41.9 m/s (150.1 km/h).
Since early 2006 the HMS has been providing official weather
warnings for the public. Warnings for windstorms, heavy precip-
itation, heavy snowfall, fog, icing, thunderstorms, heat waves
and very low temperatures are published on the HMS Web site
and transmitted to the Hungarian Disaster Recovery Authority.
On 20 August 2006, a very severe cold front reached the
capital of Hungary at 9:00 pm, whilst simultaneously the
traditional King St. Steven’s Day fireworks started. The front
with a thunderstorm supercell generated heavy precipitation
and wind gusts with a peak of 34.1 m/s (132.1 km/h). More
than one million people gathered on the Danube bank and,
despite correct forecasts, there were four fatalities and dozens
of injuries. This incident pointed out the urgent need for the
refinement of collaboration between state authorities and
meteorologists and the need for information packages for the
public.