Once the thunderstorm has formed, the downdrafts in the cumulonibus cloud causes the remaining water molecules to freeze into solid states of ice and hail. The ice particles, containing a positive charge, is separated by the updrafts, while the hail particles that are negatively charged are moved byt the downdrafts. This basically separates the differently charged particles in the storm cloud. During the thunderstorm, the Earth's surface is composed of a positive charge.
Because opposites attract, the negative charged particles on the lower cloud :caused by the downdraft) tries to contact the positive charged particles upon land. The negative charges, once strong enough to resist against air resistance, flows downward to the stepped leader, climbs up elevated objects of trees and other objects and contacts the negative particles. Once this happens, a strong electrical current inputs the positive charges in the cloud. This creates a return strike of lightning. The high voltage of electricity comprised within lightning is capable of releasing enough heat energy to ignite a fire.
High winds are known to cause all ranges of damage, depending upon their strength. Infrequent wind gusts can cause poorly-designed suspension bridges to sway. When wind gusts are at a similar frequency to the swaying of the bridge, the bridge can be destroyed easier, such as what occured with the Tacoma Narrows Bridge in 1940. Wind speeds as low as 23 knots can lead to power outages due to tree branches disrupting the flow of energy through power lines. While no species of tree is guaranteed to stand up to hurricane-force winds, those with shallow roots are more prone to up-root, and brittle trees such as eucalyptus, sea hibiscus, and avocadoare more prone to damage.
Hurricane-force winds cause substantial damage to mobile homes, and begin to structurally damage homes with foundations. Winds of this strength due to downsloped winds off terrain have been known to shatter windows and sandblast paint from cars. Once winds exceed 135 knots, homes completely collapse, and significant damage is done to larger buildings. Total destruction to man-made structures occure when winds reach 175 knots. The Saffir-Simpson scale and the Enhanced Fujita scale (TORRO scale in Europe) were designed to help estimate wind speed from damage caused by high winds related to tropical cyclones and tornadoes, and vice versa.
Dry lightning is a term in the United States for lightning that occurs with no precipitation at the surface. This type of lightning is the most common natural cause of wildfires. Pyrocumulus clouds produce lightning for the same reason that it is produced by cumulonimbus clouds. When the higher levels of the atmosphere are cooler, and the surface is warmed to extreme temperatures due to a wildfire, volcano, etc., convection will occur, and this convection produces lightning. Therefore, fire can beget dry lightning through the development of more dry thunderstorms which cause more fires.
Heat waves, droughts, cyclical climate changes such as El Nino, and other weather patterns can also increase the risk and alter the behavior of wildfires dramatically. Years of precipitation followed by warm periods have encouraged more widespread fires and longer fire seasons. Since the mid 1980s, earlier snowmelt and associated warming has also been associated with an increased in length and severity of the wildfire season in the Western United States
Fire intensity also increases during daytime hours. Burn rates smoldering logs are up to five times greater during the day due to lower humidity, increased temperatures, and increased wind speeds. Sunlight warms the ground during the day and causes air currents to travel uphill, and downhill during the night as the land cools. Wildfires are fanned by these winds and often follow the air currents over hills and through valleys. Fires in Europe occur frequently during the hours of 12:00 pm and 2 pm. U.S. wildfire operations revolve around a 24-hour fire day that begins at 1000 hours due to the predictable increase in intensity resulting from the daylight warmth.
In mid-latitudes, convective precipitation is intermittent and often associated with baroclinic boundaries such as cold fronts, squall lines, and warm fronts. Elsewhere, the wet season is the time of year, covering one or more months, when most of the average annual rainfall in a region falls. Areas with wet seasons are dispersed across portions of the tropics and subtropics. Savanna climates and areas with monsoon regimes have wet summers and dry winters. Tropical rainforests technically do not have dry or wet seasons, since their rainfall is equally distributed throughout the year. Some areas with pronounced rainy seasons will see a break in rainfall mid-season when the intertropical convergence zone or monsoon trough move poleward of their location during the middle of the warm season. When the wet season occurs during the warm season, or summer, rain falls mainly during the late afternoon and early evening hours. The wet season is a time when airquality improves, freshwater quality improves, and vegetation grows strategies for the wetter regime. Unfortunatly, the previous dry season leads to food shortages into the wet season, as the crops have yet to mature. Developing countries have noted that their populations show seasonal weight fluctuations due to food shortages seen before the first harvest, which occurs late in the wet season.
Tropical cyclones, a source of very heavy rainfall, consist of large air masses several hundred miles across with low pressure at the centre and with winds blowing inward towards the centre in either a clockwise (southern hemisphere) or counterclockwise (northern hemisphere). Although cyclones can take an enormous toll in lives and personal property, they may be important factors in the precipitation regimes of places they impact, as they may bring much-needed precipitation to otherwise dry regions. Areas in their path can recieve a years worth of rainfall from atropical cyclone passage.
Monsoons are seasonal wind shifts which lead to long-lasting wet season which produce a bulk of the annual precipitation in areas such as southeast Asia, Australia, western Africa, eastern South America, as well as Mexico. Widespread flooding can occur if rainfall becomes excessive, which can lead to landslides and mudflows in mountainous areas. Such floods cause rivers to leave their banks and homes to go uinderwater. Floods can be exacerbated by fires during the previous dry season, which cause soils which are sandy or composed of loam to become hydrophobic, or water repellent. There are various ways government organizations help their residents deal with wet season floods. Flood plain mapping is conducted, whicg helps diagnose what areas are more prone to flooding. Instructions on how to control erosion through outreach is also done via telephone or the internet.
Flooding waters that occure during Monsoon seasons can often host numerous microorganisms or protist, bacterias, and virus. These disease-agent organisms thrive and spread within contaminated waters of Monsoon floodings. Other disease carriers of mosquitoes and flies lay their eggs within the contaminated water. If exposed to flood waters, these disease-agents have high possibility of entering the blood vessels of human bodies and have capabilities causing infections of food borne and waterborne diseases. Parasitic organisms that live off the nutrients of other organisms, that also be found contained within the flood waters and also present a risk of infecting diseases.
Diseases that can ber infected with exposure to flood waters include: Malaria, Cholera, Thphoid, Hepatitis A, and the Common cold.
Possible infections of trenchfoot can also occur when exposed to extended periods of time in flooded areas. Trenchfoot developes when a person's feet is exposed with wet conditions for long periods of time. When infected with trenchfoot, a person's feet may feel itch or tingling sensations. If left untreated, swellings of blisters may appear along with the feel of numbnessand pain. Skin upon infected areas will soon peel off. pain developed from leg cramps to a commom with the infections of trenchfoot.
Acid raon is a form of precipitation, where the water molecules presented have a unusual decrease in ph levels. Acid rain can often occur during the weather phenomenon of a thunderstorm. The voltage of electricity release by lightning is powerful enough to split nitrogen molecules in the atmosphere into seperate atoms. These nitrogen atoms are reactive enough to form compounds with the water molecules presented in rain, forming nitric acid, a form of acid rain. The properties of acid rain are able to dissolve structure created out of minerals containing cacite (calcium carbonate). The acid rain reacts with the carbon molecules compost within the calcite, while also releasing calcium atoms. This process then wears and dissolves away structures made of limestone and other minerals containing calcite.
Other than the damage it does to infrastructures and buildings of limestone, acid rain can also produce risk and harm towards marine wildlife through increases in acidity. Tissues of vegetations are also presented with the risk of being damaged. Acid rain can also increase acidity in soil particles, which decrease the nutrients presented in harmed soil as well as encourage the presence of certain disease-agent microorganisms. Besides occuring within the presence of thunderstorms, acid rain can also occur in dense populated areas. Dense populated areas often have high usage of energy source, which releases greenhouse gas. This can mix with water molecules presented in the atmosphere, creating acid rain. The gas particles released by volcanic eruptions can also allow acid rain to form.
A dust storm is an usual form of windstorm that is characterized by the existence of large quanities of sand and dust particles in which are carried by moving air. Dust storms frequently develope during periods of droughts and over arid and semi-arid regions, when less moisture is being presented within soil particles, which reduces their density and cause it to be easier to lift by moving air. Dust storms generally occur for only a few minutes before subsiding.
Dust storms have numerous hazards and are capable of creating deaths when actions are not taken carefully. During the occurance of a dust storm, visibility can be reduced dramatically, making it harder to see. This can cause exposure to these weather phenomena for extended periods of time. Reduction in visibility causes the most damage within traffic areas. Risks of collisions with other automobiles can occur within areas of dust storms can be also exposed to risks of crashing when flying along busy air routes or landing, due to the fast winds and reduction of visibility. The amount of oxygen intake by resiratory organs can decrease as well, resulting in possible suffocation. Damage can also be inflicted upon external optical organs of the eyes. Dust storms can produce many issues for agricultural industries as well. Soil erosion is one of the most common hazards within a dust storm, decreasing lands availity for producing crops. Dust and sand particles associated in dust storms can cause severe processes of weathering to occur upon infrastructures and rock formations. Nearby bodies of water can be polluted by the settling of dust and sand, causing death amoung aquatic organisms. Decrease in exposure to radiation can affect plant growth, as well as provide insulation to the heat from infrared radiation, causing increases in temperature.
Dust and sand particles associated in dust storms can also be carried away form their original area thousands of milesto other geographic locations by moving air streams. While this does provide hazards for countries recieving these dust and sand particles, they also provide many benefits to certain areas. Many rainforest, like the Amazon, rely on the settling of dust and sand particles from deserts to recieve nurtients required for plant growth. All dust storms don't occur naturally. The lost of vegetation by human activites can also cause dust storms to occur. An example would be the Dust Bowl phenomenon that happened during the 1930s.
Dust storms can be classified into different weather systems based upon how they develop. Dust storms can be formed by bordering of cool and warm air fronts, resulting in the formation of gust system presented in dust storms. This type od dust storm can be considerd an extratropical cyclone. Dust storms that form by the outflow boundary of a dissipating thunderstorm, like the haboob, can be consider a form of mesoscale convective complex.