A hurricane’s deadly forces
Hurricanes have an arsenal of effects that can destroy property and cause loss of life. The combination of water and wind can have devastating impacts on nature and man. Learn what these mortal features can do and how to survive them.
Storm Tides and Waves
Storm surge is just the rise in water which floods the coast as water is pushed onshore by powerful winds, and to a much lesser level very low pressure. It’s important that you know the tides of the coastal area where you’re located. By way of example, a lot of places on the Gulf coast have quite small tidal ranges, whereas locations on the U.S. east coast have large tidal ranges. It makes a substantial difference on the consequences to the shore if a hurricane moves ashore during a low or high tide in a place where the tidal range is large. Today, inland flooding causes the biggest loss of life. In the past, when hurricane forecasting technology was much less sophisticated, storm surge was the reason for most deaths. It’s ideal to leave a structure which could be affected by the storm tide of a hurricane. The force from sea water is extremely powerful and can destroy a house easily. High waves take the debris from destroyed buildings which are on the shore that batter other structures farther inland. Houses built on stilts have a much greater survivability from surge damage. Nevertheless, it’s wise not to”ride out” a hurricane and evacuate to a safer location.
Hurricanes create strong sustained winds that have the capability of destroying structures and toppling trees and power lines. The Saffir-Simpson hurricane scale gives an estimate on the type of wind damage that can be expected with various categories of hurricanes. A major hurricane is thought to be a class 3 or higher. Strong winds can blow off in garage doors, break windows, or lift roofs from homes. Make sure that you have shutters or plywood to cover windows properly during a hurricane. Also, know how structurally sound your roof and garage doors are so that they will not fail in the event of high winds. If you’re in a flood zone, evacuate to higher ground. If you do not have a basement, find a small room on the bottom floor with no windows near the middle of the home to stay.
Tornadoes are many times associated with land falling tropical cyclones. Most of the tornadoes occur within 24 hours of land fall, even though it’s possible for tornadoes to still happen two or three days later still associated with the circulation. The largest hurricane associated tornado outbreak on record occurred with Hurricane Ivan in 2004 with 123 tornadoes. Contrary to their Midwest cousins, tornadoes on average are weaker in hurricanes. There is usually a weaker signature on radar and hail almost never accompanies them. Stronger land falling hurricanes have a greater potential to produce tornadoes than weaker ones. Tornadoes occur with land falling hurricanes as the storm moves over land and encounters greater low level friction from the property. This slows the wind at the surface more than higher aloft, adding to vertical wind shear. It’s this growth in wind shear that sets up an environment favorable for tornado development. Follow the same safety guidelines for high winds to safeguard you and your family against the harmful effects of tornadoes.
All hurricanes don’t produce severe flooding. There are several factors that contribute to the flooding potential of a hurricane or weaker tropical cyclone. The most important element is the rate of motion. If a tropical cyclone moves into an area where steering currents from the winds aloft are weak, very heavy rain can result. It is possible for the tropical cyclone to be nearly stationary for days resulting in very heavy rain amounts of 40 to 50 inches or more. Rainfall amounts are also affected by the terrain of a place. Mountains cause an added lift to occur, improving rain rates on the windward slopes. The surrounding environment in which the hurricane forms is another consideration. If a hurricane forms in the deep tropics, it usually can tap a deeper source of deep layered moisture. Hurricanes which form in higher latitudes have a greater prospect of entraining dry air from mid latitude weather systems restricting moisture. When a tropical cyclone is coming, understand the potential for heavy rainfall to make flooding or flash flooding where you live.
Summary The best way to survive the effects of a hurricane is by staying informed.