Extreme storms and hurricanes
Devastating storms and hurricanes, along with floods and droughts, have caused the deaths and suffering of millions of people around the world. The World Meteorological Organization warns – due to climate change, these natural disasters will become more frequent.
Storm is a meteorological phenomenon whose manifestations may include strong winds, thunder and lightning (thunderstorms), heavy rain or snowfall, as well as wind-blown dust and sand (sandstorms) or snow (snowstorms). The strict definition of a storm from the point of view of meteorologists is when the wind speed exceeds 88 km/h, but in practice the popular use of the term includes weaker winds. At wind speeds above 117 km/h, this meteorological phenomenon is defined as a hurricane. The damages from strong storms are very different:
- Strong winds that characterize each storm can damage or destroy vehicles, buildings, infrastructure and other objects.
- Lightning that accompanies thunderstorms can endanger people's lives and cause fires.
- Another danger posed by thunderstorms is the chemical reactions between nitrogen, oxygen and water vapor in the atmosphere, which are carried out with the help of the enormous energy given off by lightning. As a result of these reactions, acid rain is formed, which has a destructive effect on the infrastructure and degrades plant tissues, increases the acidity of water bodies and causes the extinction of various aquatic and terrestrial organisms.
- One of the most common side effects of storms – hail – can damage the roofs and windows of buildings and cars, destroy crops, and can endanger the health and lives of humans and animals.
- Heavy snowfall can disrupt public infrastructure and services. Air and ground transport can be severely delayed or even stopped altogether.
Cyclone – We call a cyclone the spiral ascending movement of air in the direction from the periphery to the center of the air mass. The cyclonic winds blow counterclockwise in the Northern Hemisphere and clockwise south of the equator. Cyclones cover large areas, mainly in temperate latitudes. Their diameter reaches 1500 km and height – up to 12 km. There are two types of air masses in each cyclone – hot and cold. The warm air masses are located in its southern part. The cold air masses cover a larger area and are located to the north. The cold sector of the cyclone moves at a higher speed, gradually catching up and conquering the space covered by the warm sector. This stops the cyclone. Cyclones usually move in series of 2 to 5 days. In the temperate latitudes of the Northern Hemisphere, their direction is from west to east, having a strong influence on the climate of Europe and Bulgaria. So-called tropical cyclones occur in the tropics.
Tropical cyclone – The tropical cyclone is a fast-spinning stormy system characterized by a low-pressure center, closed atmospheric circulation, strong winds, thunderstorms that cause heavy rain and / or gusts (strong gusts of wind). Depending on its location and strength, a tropical cyclone is called by different names: hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, or simply cyclone. The hurricane is a severe tropical cyclone that occurs in the Atlantic or Northeast Pacific, and a typhoon occurs in the Northwest Pacific. In the Indian Ocean, the South Pacific or the South Atlantic, such storms are simply called "tropical cyclones." The reason for the formation of tropical cyclones is the strong upward vortex movement of air over ocean water, the rapid change in atmospheric pressure in altitude and the rapid condensation of water vapor. As a result, the formed winds gain very high speed and are directed from the ocean to the land, causing significant devastation. In their way, they destroy buildings, bridges, overpasses, roads, complicating the efforts to transport food, clean water and medicine to disaster areas. Tropical cyclones often cut off electricity, disrupting vital communications and rescue operations. The damage to the affected areas is significant. Storm tides (sea level rise caused by tropical cyclone) are usually the worst effects of tropical cyclones moving from water to land – statistically accounting for about 90% of all deaths caused by such extreme natural events. The relatively rapid rise in sea level could push inland for miles, cutting off the evacuation routes. There are other disturbing changes. Areas affected by tropical storms are shifting in the direction of the poles. This is probably due to the expansion of the tropics due to higher global average temperatures. Changing patterns of tropical storms – such as the displacement of the North Atlantic – could put much more property and lives at risk.
Although scientists are unsure whether climate change will increase the number of hurricanes, there is growing confidence that warmer ocean temperatures and higher sea levels will increase their intensity and impact. Based on computer modeling in the case of an increase in the average temperature by 2oC, it is assumed that the wind speed of the hurricanes with the highest degree of danger will increase by up to 10 percent and humidity by 10-15%. This, in turn, would lead to much greater damage and an increase in deaths if timely measures are not taken to protect vulnerable areas, along with actions to limit further climate change.
Tornado – A tornado, is a strong atmospheric vortex that forms a rotating column of air connecting the earth's surface to the clouds. Tornadoes have different shapes and sizes, but in the most common case they are in the form of a funnel, whose narrow end rests on the ground, and the expanding body of the funnel is surrounded by a cloud of debris and dust. In most tornadoes, the wind speed is up to 180 km/h, their surface diameter is about 80 m, and the distance they travel before dispersing is several kilometers. Tornadoes with much higher wind speeds have also been observed, the impact of which covers much larger areas. Tornadoes can strike both on land and over water bodies. Water tornadoes are characterized by a spiral funnel-shaped pillar connecting a large cumulus or cumulonimbus cloud with the water surface. Such spiral pillars often form in areas close to the equator and are less common in temperate latitudes. Tornadoes have been observed on all continents except Antarctica. The most affected by these natural phenomena are the central and southeastern regions of the United States. Tornadoes are sometimes seen in Asia, southeastern South America, much of Europe, western and southeastern Australia, and South Africa. Although rare, tornadoes are also registered in Bulgaria. There are technical means of predicting tornadoes shortly before their formation.
Determining the effects of tornado damage is done using the so-called Fujita Scale, whose degrees determine the intensity of a tornado based on the severity of the damage caused along the way. According to this scale:
- Grade F0 refers to tornadoes characterized by wind speeds between 60 and 117 km /h. Damages include broken tree branches, damaged TV antennas and road signs.
- Grade F1 – wind speed between 117 and 181 km/h, broken windows, inverted cars, damaged structures.
- Degree F2 – wind speed between 181 and 250 km/h, uprooted trees, removed roofs.
- Degree F3 – wind speed between 250 and 320 km/h, devastated forests, destroyed buildings.
- Grade F4 – wind speed between 320 and 420 km/h, significant damage, including the removal of buildings from foundations.
- The highest levels F5 and F6 are characterized by wind speeds of over 420 km/h, reaching 612 km/h. These are the tornadoes of the greatest intensity, destroying buildings, blowing up trains and all kinds of heavy vehicles.
One of the countries with the highest frequency of tornadoes in its territory is the United States: the wide terrain and the lack of mountains to stop the course of the natural event are the main reasons that make this country one of the most affected. Up to 1,200 tornadoes are registered annually in North America.
