HURRICANES

Hurricane – a rotating tropical storm with winds of at least 74 mph that develops over the Atlantic or Eastern Pacific oceans Called cyclones when they develop over the Bay of Bengal Called typhoons when they develop in the western Pacific.

WHERE THESE STORMS DEVELOP

Three Main Parts to a Hurricane: 1. Eye The low pressure center of the hurricane miles wide Calm part of the storm 2. Eyewall A ring that surrounds the eye Fastest and most violent winds of the storm 3. Feeder Bands/ Rainbands Bands of rain with gusty winds First signs of the coming storm HURRICANE ANATOMY:

FEEDERBANDSEYEWALLEYE HURRICANE ANATOMY:

Trade winds of the north and south will meet, causing tropical disturbances These disturbances take energy from the warm water at the equator and develop into tropical depressions As the depression moves across the ocean, its energy grows It becomes classified as a tropical storm when winds reach 39 miles an hours. TROPICAL STORM

Very few tropical storms develop into hurricanes because the conditions have to be just right. They develop only around the equator because they use the warm, moist air as fuel. What do we know about convection? HOW HURRICANES FORM:

CONVECTION AND AIR DENSITY A convection cell can occur in a room! Convection currents like this also occur in the atmosphere.

Very few tropical storms develop into hurricanes because the conditions have to be just right. They develop only around the equator because they use the warm, moist air as fuel. The warm air rises, causing lower air pressure below. New, surrounding air fills in and becomes warm and moist as well, then rises. This air then cools and forms clouds in bands around the eye. The cool dry air sinks in the eye and between the bands of clouds. HOW HURRICANES FORM:

Hurricanes will weaken when they hit land because they lose their source of energy (i.e. the warm, moist ocean water that drives the circulation) However, they can move far inland, dumping tons of rain and causing excessive wind damage before they die out. HURRICANE IMPACT ON LAND

SAFFIR-SIMPSON HURRICANE CATEGORY SCALE

A storm surge is an abnormal rise in the sea level generated by a storm It is the greatest threat to life and property from a hurricane Causes coastal flooding Storm surges can reach 20 feet tall and extend 100 miles inland 9 out of 10 deaths from Hurricanes are caused by storm surges WHAT IS A STORM SURGE?

Great Galveston Hurricane (1900) Deadliest hurricane in history Category 4 12,000 deaths Great Labor Day Hurricane (1935) Category deaths Hurricane Katrina (2005) Category 5 Top 5 deadliest hurricanes Nearly 2000 deaths More than $100 billion dollars in damage (costliest natural disaster in history) HURRICANES IN HISTORY:

Meteorologists can determine the location and intensity of a tropical storm once it forms. At the U.S. National Hurricane Center in Florida they use satellite imagery, airborne reconnaissance, and computer-model projections to track and predict when these storms will head ashore. NOAA and the U.S. Airforce Reserve send in “Hurricane Hunters” to collect information. They measure: Pressure Dew point Temperature Wind speed HOW ARE THE STORMS PREDICTED AND TRACKED?