Weather or Not
Day 5 - Hurricanes
By: harper mcdonald and piper stilwell
hurricanes - how they form
Hurricanes must form in warm oceans (specifically the Atlantic Ocean) that are at least 81 degrees Fahrenheit. Warm, moist air begins to rise, which causes an area of low pressure to form near the surface. This air warms up as it rises, forming a cycle. This eventually forms large storm clouds because of the warm air cooling. The Coriolis effect causes the storm to begin spinning. The storm moves around, destroying nearly everything, fueling on the ocean's heat.
hurricanes - where and when they occur
Hurricanes form over the Atlantic Ocean or the eastern Pacific Ocean. Hurricane season is officially June 1st to November 30th, but hurricanes are the most common from late summer throughout the fall.
hurricanes - instruments and scales
Beaufort Wind Scale
A system for estimating and reporting wind speeds. It is based on the visible effects of wind upon land objects (such as vegetation) and/or sea surface conditions such as white caps and foam.
Blocking High
A high pressure system that is warm in the air and cold at the surface. Such a high will move very slowly, tending to move westward during the intensification of the storm and eastward during the slowing down of the storm. It prevents the movement of cyclones across its latitudes by causing a split in westerly winds. A hurricane may be steered toward or away from land by one of these.
Data Buoys
These are instrumented buoys placed throughout the Gulf of Mexico and along the Atlantic and Pacific coasts of the United States that collect and relay data or information on air and water temperature, wind speed, air pressure, and wind conditions through several sources. For hurricanes, these buoys are used to gather information to help predict hurricanes strengthening or weakening and direction of movement.
Saffir-Simpson Scale
This scale classifies hurricanes based on their intensity, and is used to predict how damaging the hurricane will be to property.
Category 1 [Minimal]
Damage primarily restricted to shrubbery, trees, and unanchored mobile homes; no substantial damage to other structures; some damage to poorly constructed signs
Low lying roads inundated; minor damage to piers; small craft in exposed anchorages torn from moorings
Category 2 [Moderate]
Considerable damage to shrubbery and tree foliage, some trees blown down; major damage to exposed mobile homes; extensive damage to poorly constructed signs and some damage to windows, doors and roofing materials of buildings, but no major destruction to buildings
Coastal roads and low lying escape routes inland cut off by rising water about 2 to 4 hours before landfall; considerable damage to piers and marinas flooded; small craft in protected anchorage torn from moorings
Evacuation of some shoreline residences and low lying areas required
Category 3 [Extensive]
Foliage torn from trees; large trees blown down; poorly constructed signs blown down; some damage to roofing, windows, and doors; some structural damage to small buildings; mobile homes destroyed.
Serious flooding along the coast; many small structures near the coast destroyed; larger coastal structures damaged by battering waves and floating debris
Low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; flat terrain 5 feet or less above sea level flooded up to 8 or more miles inland
Evacuation of low lying residences within several blocks of shoreline may be required
Category 4 [Extreme]
Shrubs, trees, and all signs blown down; extensive damage to roofs, windows, and doors, with complete failure of roofs on many smaller residences; mobile homes demolished
Flat terrain 10 feet or less above sea level flooded inland as far as 6 miles; flooding and battering by waves and floating debris cause major damage to lower floors of structures near the shore; low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; major erosion of beaches
Massive evacuation of all residences within 500 yards of the shore may be required, as well as of single story residences in low ground with 2 miles of the shore
Category 5 [Catastrophic]
Trees, shrub, and all signs blown down; considerable damage to roofs of buildings, with very severe and extensive damage to winds and doors; complete failure on many roofs of residences and industrial buildings; extensive shattering of glass in windows and doors; complete buildings destroyed; small building overturned or blown away; mobile homes demolished
Major damage to lower floors of all structures less than 15 feet above sea level within 1500 feet of the shore
Low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; major erosion of beaches
Massive evacuation of residential areas on low ground within 5 to 10 miles of the shore may be required