A Lesson on European Tornadoes and Related Research (credit: Britannica.com, The Conversation, American Meteorological Society, Smithsonian.com, NOAA, Horizon Magazine, UStornadoes.com, Keraunos.org)
DISCUSSION: While an average of over 1000 tornadoes are reported each year in America, our friends in Europe receive an average of 300 tornadoes per year though much fewer are reported. If Europe was one country, it would knock Canada out of second place for tornado production each year. An article highlighted the European part of Russia as the leading countries for tornadoes due to Russia’s large size. Coming in second place with more than 30 tornadoes per year is the U.K. The strongest tornadoes tend to span between Germany and northeast France towards Poland.
The formal study of European tornadoes began in the 17th-century when Italian astronomer and mathematician Geminiano Montanari analyzed a tornado that occurred in the Veneto region of Italy in July 1686.Digging deeper into European tornado history revealed that before the end of World War II, European scientists and meteorologists were the leading tornado researchers. One reason for this was that the word tornadowas banned by the Weather Bureau and the government didn’t want to cause panic.One AMS study stated that after 1950, the interest in European tornadoes declined when the majority of tornado reports were collected outside the national meteorological services.
Figure: The AMS study stated “(a) The spatial distribution of tornado reports (tornadoes per 10,000 km2) in Europe in between 1950 and 2015 on a 50 km × 50 km grid, shaded according to the scale. (b) The population density (inhabitants per km2) estimated for 2015, shaded according to the scale. The population density was obtained from SEDAC (2015). The four main regions of Europe are also indicated (dashed lines).”
The study further explained how the European Severe Weather Database (ESWD), of the European Severe Storms Laboratory, obtained 5,478 tornado reports from 1950 – 2015 (seen in the figure). ESWD records indicated that the tornado season for most of Europe occurs between May to August with a peak in July. Eastern Europe sees most of their tornadoes during the spring and early summer months. Northern Europe’s tornado season is from mid to late summer. Finally, southern Europe most frequently receives tornadoes and waterspouts in the Mediterranean Sea during the fall and early winter.
During that 1950 – 2015 timeframe, European tornadoes resulted in 4,462 injuries, 316 fatalities and damages estimated at more than €1 billion. A recent study explained that the Enhanced Fujita (EF) scale is the leading scale for ranking European tornados, though the Fujita scale and Torro scale are also used. The Torro scale was first developed in and is still used by the U.K.; it is a pure wind speed scale. The paper further expressed that to be most effective in Europe, the EF-scale damage indicators should be modified to represent European construction techniques.
Looking ahead, tornadoes will continue to impact European countries. Additionally, there are many active areas of European tornado research including the best scale for classifying tornado damage. So, even though it isn’t tornado season here in the U.S., keep your eye out for tornadoes and related research in Europe throughout the year!
To learn more about European weather, click here.
© 2018 Meteorologist Amber Liggett
DISCUSSION: To the first order, the temperate oceanic and continental climate that governs the conditions across much of Europe can be characterized by relatively cool temperatures during the summer months. Over the course of the last few days, however, most of Europe has been under the influence of a significant summer heat wave where many long-standing temperature records have already been challenged. Recently, daily maximum temperatures have risen well above 30°C (~86°F) in southern England, 35°C (~95°F) in most of western Europe, and over 38°C (~100°F) over southern and central Spain. The heat is creating noticeable strain on transportation operations (by virtue of cancellations and delays) in order to maintain safety, and multiple forest fires have ignited, including the recent Greek wildfire that has claimed 92 lives.
So what is the culprit for the development of this heat wave? It all begins with a robust ridge of high pressure that is situated between the middle and upper-levels of the atmosphere. Geopotential height, a measure of the height of a constant pressure surface above the mean sea level, is a useful diagnostic tool and proxy for determining the strength of a ridge or trough affecting a region, and higher (lower) heights usually correspond to warmer (cooler) surface temperatures. During this heat wave, most of Europe has been faced with 500 hPa (~5,500 meters above sea level) geopotential heights that are 2-3 standard deviations above normal for this time of year, which equates to anywhere from 5,800-5,900 m. Specifically, most of western Europe At the surface, maximum temperatures have been 6-10°C above normal. Furthermore, the positioning of the jet stream also favors south-to-north advection of warmer air in the upper levels.
The excessive warmth is expected to continue once again by the end of this week as current Global Forecast System (GFS) model runs indicate the development of another high pressure system and upper-level ridge. Southwesterly winds will once again facilitate robust warm air advection over much of Europe and keep temperatures several degrees above normal as the air above the surface warms considerably. In addition, moisture over western France and the UK will likely yield heat indices that exceed 38°C (~100°F) there while much warmer temperatures are forecast over Spain. Under this level of warmth, it is imperative to stay hydrated and cool to escape potentially harmful heat-related illnesses, especially in regions that are not adapted to very warm conditions.
To learn more about other high-impact weather events across Europe, be sure to click here!
© 2018 Meteorologist Brian Matilla
DISCUSSION: Over the past week, a series of wildfires have been burning across the Attica region of Greece. The first of these fires began in Kineta, a beach town around 30 miles west of Athens, and the second major fire started northeast of Athens in the Penteli and Rafina areas, primarily centered in the coastal village of Mati. As of Sunday, the death toll from these fires rose to 91, making these Greece’s worst fires in over a decade.
These fires, which drove swarms of people to the sea seeking refuge from the flames, are suspected to have been the result of arsonists looking to loot homes abandoned during the fires. Although the fire was likely initially human-caused, the climate and weather in the region provided an environment conducive to exacerbating the flames. The Attica region of Greece typically experiences dry summers and shorter wet periods in the winter; however, this region saw a drier winter this year, leading to drier forests that are more vulnerable to fires. Fires in this region are common during the hot, dry summers, and while the drier than normal winter may have been a factor in how extreme these fires have become, it is likely that high winds played a bigger role.
Dry conditions and hot temperatures can provide an environment likely to burn when a spark is introduced, however, it is strong winds that can cause fires to spread across more area very quickly. Wind gusts reaching record speeds of up to 120 km per hour (around 75 miles per hour) and average wind speeds of 65 km per hour (around 40 miles per hour), were recorded in the Attica region last week when the fires began. Winds provide oxygen to help fuel the fires while also working to push the fires across more land area. Stronger winds can speed up the spread of the fires, making it more difficult for them to be contained.
To learn more about other high-impact weather events occurring across Europe, be sure to click here!
©2018 Meteorologist Stephanie Edwards