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Lessons on the Lake -> Chapter 8 -> Hurricanes

Activity: Hurricanes

Those of us who live in the Lake Pontchartrain Basin are always wary of tropical storms or hurricanes that enter the Gulf of Mexico. These severe weather patterns are usually the result of meteorologic activity in the south Atlantic Ocean or in the Caribbean Sea from May through November. Hurricanes are born and grow in the steamy tropics. The connection is energy transfer and the role of water in that process. The sun and the ocean are the furnace for the formation of a hurricane. Toward the end of the summer, the accumulated solar warmth in ocean waters may raise the sea surface temperature to as much as 26.5 degrees Celsius.

Convert 26.5 degrees Celsius to ______________degrees Fahrenheit.
(HINT: multiply by 9; divide by
5; add 32)

In the tropical Atlantic, this heating of the ocean’s surface can result in the formation
of a weak low pressure system with scattered, thin clouds. If the low pressure system
is pushed toward the west by the trade winds, it may gain strength with increasing
winds and thickening clouds. In this manner, the low pressure system may advance to
a tropical depression, then to a tropical storm, and finally to hurricane strength.

About one of every eight tropical depressions becomes a tropical storm, and the chance of a selected tropical storm becoming a hurricane is only about 60%.

Water provides the transportation for a hurricane’s energy, similar to the way it may move heat from the furnace to a radiator in your school’s heating system. The solar energy in the ocean causes water to evaporate from the surface, bringing heat with it. The water vapor condenses, forming hurricane clouds, and the latent heat is released into the air. This is the power that drives the hurricane. As the warm, moist air from the sea surface cools and the water vapor condenses, huge cumulonimbus clouds form. Precipitation forms in these clouds, and rain falls back to the sea surface in a continuous process. The amount of rain that falls gives us an idea of the strength of the storm. A well-developed hurricane can deliver 24 cm (about 10 inches) of rain per day!

Hurricane Definitions

Tropical Disturbance:
Poorly organized counterclockwise circulation.

Tropical Storm Watch:
The possibility of winds 39-73 mph within 48 hours.

Tropical Depression:
Organized counterclockwise circulation,
winds up to 39 mph.

Tropical Storm Warning:
The likelihood of winds 39-73 mph within 24 hours.

Tropical Storm:
Well-organized counterclockwise circulation, winds 39-73 mph.

Winds 74 mph or more. Heavy rains and
storm surge.

Hurricane Watch:
The possibility of hurricane force winds in
excess of 74 mph within 48 hours.

Hurricane Warning:
The likelihood of hurricane force winds within 24 hours.

Saffir-Simpson Hurricane Scale Ranges

Scale # (Category)






Winds (mph)





156 or greater

Storm Surge (Feet)





18 or greater

Damage (impact)







  1. Focus on the impact of hurricanes on the natural and cultural environments
    of the Lake Pontchartrain Basin.
  2. Plot data of major hurricanes that have affected the Lake Pontchartrain
    Basin on a hurricane tracking map.
  3. Predict the effects of a major hurricane on the Lake Pontchartrain Basin.
    Understand the relationships among healthy wetlands, coastal erosion, and
    hurricane impact on the Lake Pontchartrain Basin.


  • Hurricane Data Sets, Student Activity Sheet, and Hurricane Tracking Map (all contained in student download)
  • Construction paper
  • Colored pencils

Getting Ready:

  • Discuss hurricane formation prior to this in a unit on meteorology.
  • Make copies of student activity sheet and hurricane tracking map in student download
  • Research impact/effects of hurricanes in the Lake Pontchartrain Basin.


  • On a hurricane tracking map, using a different color for each hurricane, plot the path of each storm data set provided.
  • Glue or tape student tracking maps on construction paper. Display in the classroom,
    hallway, cafeteria, or library.
  • Complete student activity sheet in student download.

The male Great Blue Heron chooses the nesting site, and if he can convince a female that he's chosen a good spot, she will build a nest and lay her eggs.

  1. Introduction
  2. Essential Questions
  3. Global Climate Change
  4. Are Sea Levels Rising?
  5. Subsidence and Erosion in the Basin
  6. Activity: Thinking at Right Angles
  7. Activity: Linking Lake Factors
  8. Hurricanes
  9. Activity: Subsidence and Erosion
  10. Activity: C-Mail
  11. Activity: The Pontchartrain Picayune
  12. Activity: Multimedia Presentation
  13. Activity: Help! I'm Up to my Hips in Water!