Saturday, September 25, 2010
FLOODS. (PART 2)
I was really very shocked when I learned about the floods in Tennessee. It is a beautiful State where I have always wanted to build or to own my final home at the time of retirement. There is not much that I ask the Lord, to give me complete peace of mind in my elderly years, not troubles like I have had throughout young years in my lifetime. To decide where to move to, and where to relocate after my retirement, it is not an easy task for me at all. Let´s see why...
The May 2010 Tennessee floods in the United States were 1000-year floods in Middle Tennessee, West Tennessee, South Central and Western Kentucky and northern Mississippi as the result of torrential rains on May 1 and 2, 2010. Floods from these rains affected the area for several days afterwards, resulting in a number of deaths and widespread property damage.
Two-day rain totals in some areas were greater than 19 inches (49 cm). The Cumberland River crested at 51.86 feet in Nashville, a level not seen since 1937, which was before the U.S. Army Corps of Engineers flood control measures were in the Duck River at Centerville and Hurricane Mills, the Buffalo River at Lobelville, the Harpeth River at Kingston Springs and Bellevue, and the Red River at Port Royal.
In the early morning of May 4, flooding at Nashville Electric Service substation caused power failure to go out in downtown, the center of the city of Nashville. Among the buildings that lost electricity was the 617-foot (188 m) AT & T Building, the tallest building in Tennessee. Power was not expected to be restored until Friday, May 7.
Nashville/Davidson County was declared a Federal Disaster Area on May 4.
As of May 7, 30 counties have declared a major disaster areas by the federal government, with 52 submitted to receive that status. This translates to about 31 % of Tennessee currently being designated a mayor disaster area, with potential of over half the state (roughly 53%) being so declared if all that are currently submitted receive that designation by the federal government.
According to Nashville Mayor Karl Dean, damage estimates in Nashville are at about $1.5 billion not including damage to roads and bridges or public buildings, as well as contents inside buildings and residences.
Almost all schools in the area were closed including Metropolitan Nashville Public Schools, some for a week or more.
We are faithful Christians, and we are praying for the State of Tennessee. Lord have mercy!!
Thank your for visiting my site and reading my posts!!
Monday, September 20, 2010
FLOOD. (PART 1)
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Flooding may result from the volume of water within a body of water, such as a river or lake, which overflows or breaks levees, with the result that some of the water escapes its usual boundaries. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, it is not a significant flood unless such escapes of water endanger land areas used by man like a village, city or other inhabited area.
Floods can also occur in rivers, when flow exceeds the capacity of the river channel, particularly at bends or meanders. Floods often cause damage to homes and business if they are placed in natural flood plains of rivers. While flood damage can be virtually eliminated by moving away from rivers and other bodies of water, since time out of mind, people have lived and worked by the water to seek sustenance and capitalize on the gains of cheap and easy travel and commerce by being near water. That humans continue to inhabit areas threatened by flood damage is evidence that the perceived value of living near the water exceeds the cost of repeated periodic flooding.
PRINCIPAL TYPES and CAUSES.
Flooding of a creek is due to heavy monsoonal rain and high tide, and flash flooding is caused by a severe thunderstorm.
Riverine. Slow kinds: Runoff from sustained rainfall or rapid snow melt exceeding the capacity of a river´s channel. Causes include heavy rains from monsoons, hurricanes and tropical depressions, foreign winds and warm rain affecting snow pack. Unexpected drainage obstructions such as landslides, ice, or debris can cause slow flooding upstream of the obstruction.
Fast kinds: Include flash floods resulting from convective precipitation (intense thunderstorms) or sudden release from an upstream impoundment created behind a dam, landslide, or glacier.
Estuarine. Commonly caused by a combination of sea tidal surges caused by storm-force winds. A storm surge, from either a tropical cyclone or an extratropical cyclone.
Coastal. Caused by severe sea storms, or a result of another hazard (e.g. tsunami or hurricane). A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category.
Catastrophic. Caused by a significant and unexpected event, e.g. dam breakage, or a result of another hazard (e.g. earthquake or volcanic eruption).
Muddy. A muddy flood or mud slide is generated by run off on crop land. A muddy flood is produced by an accumulation of runoff generated on cropland. Sediments are then detached by runoff and carried as suspended matter or bedload. Muddy runoff is more likely detected when it reaches inhabited areas. Muddy floods are therefore a hillslope process, and confusion with mudflows produced by mass movements should be avoided.
Other. Floods can occur if water accumulates across an impermeable surface (e.g. from rainfall) and cannot rapidly dissipate (i.e. gentle orientation or low evaporation). When a series of storms are moving over the same area. Dam-building beavers can flood low-lying urban and rural areas, often causing significant damage.
Primary effects. Physical damage. Can damage any type of structure, including bridges, cars, buildings, sewer systems, roadways, and canals.
Casualties. People and livestock die due to drowning. It can also lead to epidemics and waterborne diseases.
Secondary effects. Water supplies. Contamination of water. Clean drinking water becomes scarce. Diseases. Unhygienic conditions. Spread of water-borne diseases. Crops and food supplies. Shortage of food crops can be caused due to loss of entire harvest. However, lowlands near rivers depend upon river silt deposited by floods in order to add nutrients to the local soil.
Trees. Non-tolerant species can die from suffocation.
Economic. Economic hardship, due to: temporary decline in tourism, rebuilding costs, food shortage leading to price increase, etc.
Part 2 will follow...
Thank you for reading!!
Sunday, September 19, 2010
This article is about the weather phenomenon called Tornadoes.
A tornado is often referred to as a twister. The funnel itself is the thin tube reaching from the cloud to the ground. The lower part of the tornado is surrounded by a translucent dust cloud, kicked up by the tornado´s strong winds at the surface.
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. Tornadoes come in many shapes and sizes, but are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust. Most tornadoes have wind speeds less than 110 miles per hour (117 km/h), are approximately 250 feet (80 m) across, and travel a few miles (several kilometers) before dissipating. The most extreme can attain wind speeds of more than 300 mph (480 km/h), stretch more than two miles (3 km) across, and stay on the ground for dozens of miles (more than 100 km).
Various types of tornadoes include the landspout, multiple vortex tornado, and waterspout. Waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-supercellular tornadoes that develop over bodies of water. These spiraling columns of air frequently develop in tropical areas close to the equator, and are less common at high latitudes. Other tornado-like phenomena that exist in nature include the gustnado, dust devil, fire whirls, and steam devil.
Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes in the world occur in the Tornado Alley region of the United States, although they can occur nearly anywhere in North America. They also occasionally occur in south-central and eastern Asia, the Philippines, northern and east-central South America, Southern Africa, northwestern and southeast Europe, western and southeastern Australia, and New Zealand. Tornadoes can be detected before or as they occur through the use of Pulse-Doppler radar by recognizing patterns in velocity and reflectivity data, such as hook echoes, as well as by the efforts of storm spotters.
These are several different scales for rating the strength of tornadoes. The Fujita scale rates tornadoes by damage caused, and has been replaced in some countries by the updated Enhanced Fujita Scale. An FO or EFO tornado, the weakest category, damages trees, but not substantial structures. An F5 or EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers. The similiar TORRO scale ranges from a TO radar data, photogrammetry, and ground swirl patterns (cycloidal marks) may also be analyzed to determine intensity and assign a rating of a tornado.
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