1. Roger Robertson Samuel Olson
How Hurricanes Work
Roger Robertson
Samuel Olson

2. Overview Hurricane season June 1st – November 30th
Also called cyclones or typhoons

3. Forming Forms in warm water Tropical Region
Most Atlantic Hurricanes form off the west coast of Africa

4. Parts of a Hurricane
Eye - the low pressure, calm center of circulation
Eye wall - area around the eye with the fastest, most violent winds
Rain bands - bands of thunderstorms circulating outward from the eye that are part of the evaporation/condensation cycle that feeds the storm

5. Stages
Tropical depression - swirling clouds and rain with wind speeds of less than 38 mph
Tropical storm - wind speeds of 39 to 73 mph
Hurricane - wind speeds greater than 74 mph

6. Category Wind Speed Effects 1 74 to 95 mph 2 96 to 110 mph 3
Storm surge 4 to 5 ft above normal
Some flooding
Little or no structural damage 2
96 to 110 mph
Storm surge 6 to 8 ft above normal
Trees down
Roof damage (shingles ripped off) 3
111 to 130 mph
Storm surge 9 to 12 ft above normal
Structural damage in houses
Mobile homes destroyed
Severe flooding 4
131 to 154 mph
Storm surge 13 to 18 ft above normal
Severe flooding inland
Some roofs ripped off
Major structural damage 5
>155 mph
Storm surge at least 18 ft above normal
Severe flooding further inland
Serious damage to most wooden structures

7. Weather Alerts Tropical-storm watch Tropical-storm warning
Hurricane watch
Hurricane warning