16 minutes later there was a reported rise of 2m in one hour. At 15:53 the fire brigade was mobilised and 7 minutes later access to all roads was closed. 30 minutes later at 16:30 a 3m wall of water flowed through Boscastle at 64kph. The flood reached peak level at 17:00 and cars were swept away and buildings destroyed. The rain was so heavy it was difficult to see.
The run-off from higher elevation combined with melt water from lower elevation was so forceful it broke levees and caused one of the most damaging floods the region has ever seen. The West Walker River caused extensive damage in Topaz, Coleville, California, Wellington and Nevada. It’s estimated that twelve miles of US Highway 395 have been destroyed and are going to be closed for around seven months! In Yerington and in the Mason Valley nearly 500 homes have been damaged and public and private property damaged substantially. Floodwaters deposited debris on Farmland and Damaged irrigation gates, ditches and canals.
There were a number of physical factors causing the Boscastle floods. The village suffered from heavy rainfall. Over 2 hours, 0.05mm of rainfall fell per minute. In total, over 3 million tonnes of water was added to the small drainage basin, in which two weeks of previous rainfall had saturated the ground, which it simply couldn’t hold. Both Boscastle and Thailand were at the foot of steep slopes.
The effect of Hurricane Katrina on New Orleans was extremely severe, resulting from one of the most deadly natural disasters in U.S. history. By August 30th, 2005, one day after the Category 4 storm made landfall, about 80 percent of the city of New Orleans, was flooded with some parts of the city under 20 feet of water. The flood was caused by several levees breaches, which most people didn’t believe it could breach, due to a combination of a powerful storm surge, strong winds and excess water in the bodies of water surrounding the city. After reading the author’s response, her curiosity was based on her belief that the delayed response time was due to racism. She first noticed when watching the T.V.
Why the flood happened The flood was the result of a combination of three main exceptional factors that include the location of the village, unusual weather conditions and human activity. The weather on the day of flood was considered to be the most important factor of the flood. The weather was stormy over the days in Boscastle. The localized temperatures that day were high and the surface water was unabsorbed. With effects of the local relief and the moist winds off the sea, warm moist air rose quickly resulting from the convergence of two unusual air masses.
2) How do storm surges increase the likelihood of coastal flooding during a hurricane? Storm surges have been one of the most significant hazards associated with hurricanes. A storm surge is a large volume of ocean water that is driven ashore by a land falling hurricane or tropical storm. Storm surge is a rapid rise in sea level, accompanied by large battering waves. The surge is caused by strong onshore winds forcing the ocean level to rise up and flow inland.
The Great Storm of 1987 occurred on the 15th October in that year, it was the worst storm to reach Britain for over 200 years. The days preceding the storm a depression was developing over the Bay of Biscay, just west of France. This depression was slowly drifting northwards towards the British Isles building up intensity as it went. Weather stations reported that the severe weather would not reach further north than the English Channel, therefore England were not mentally or physically ready to cope with a storm of this magnitude. The impacts of the storm were great, with wind speeds recorded of up to 120mph in Sussex and Kent.
But on August 25, 2005, when Hurricane Katrina struck New Orleans, everything changed. The levees failed, over 75% of the city was submerged in water and over 1,800 lives were lost. By the time the storm passed, over $81 billion in physical damages had been done. It is estimated that Katrina has resulted in the loss of over 230,000 jobs in Louisiana alone. When the storm struck New Orleans and the levees failed, the low-lying lands flooded at record levels.
* Impacts on Water Resources The Great Plains’ water is provided by the Ogallala aquifer, supplying more than 80% of drinking and irrigation water. With growth in population, agriculture, and the economy, demand for water has increased. This influx of growth has caused the use of water in the region to surpass the recharge rate causing the level of the aquifer to drop. If these practices continue and other resources are not found, then temperatures will increase, droughts will be more frequent, and higher rates of evaporation are to put more strain on the water supply. * Impacts on Agriculture The region’s economy depends on crops; the majority of the Great Plains is used for agriculture.
Storm surge generally 6-8 feet above normal. Some roofing material, door, and window damage of buildings. Considerable damage to shrubbery and trees with some trees blown down. Considerable damage to mobile homes, poorly constructed signs, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of the hurricane center.