Meteorological Hazards

• Tropical storms are areas of low pressure with winds moving in a spiral
• They last days to weeks and have speeds over 74mph over warm water (>27 degrees)
• Tropical storms are measured by the Saffir-Simpson scale, which categorizes them from 1-5 based on sustained wind speed and estimates potential property damage
• Tropical storms form from the equatorial regions 30N and S above the equator between the tropics of Cancer and Capricorn
• Global circulation is a world-wide system of winds that transport heat from tropical to polar latitudes
• Differential heating causes air expansion and changes in pressure, leading to wind as a result of pressure changes in the atmosphere
• High temperatures at the equator cause air to rise, creating low pressure, while air cools and sinks at around 20-30 degrees leading to high pressure
• The spin of the earth induces the Coriolis effect in the Northern hemisphere, causing winds to curve
• When the Hadley cell is complete, the air flows back to the equator as trade winds
• Hurricanes rotate counterclockwise in the Northern hemisphere due to the Coriolis effect
• Conditions for storms to form include sea temps >27 degrees, ocean depth of >70m, location between 5-20 degrees North and South, low level convergence of air, and rapid outflow of air in the upper atmosphere
• Hurricanes begin as thunderstorms and develop from warm, moist air rising to create low pressure
• The eye of a hurricane is an area of extremely low pressure surrounded by a spinning vortex of high winds and heavy rain
• Tropical storms form in the Northern Hemisphere from June-November and in the Southern Hemisphere from November-April
• Hazards caused by tropical storms include high winds, flooding, landslides, and storm surges