The Science of Disasters
EAS 201 – Written Assignment 5

1. What is the difference between a flash flood and a regional flood? Are the causes the same? Are the effects the same?

Flash Flood; are walls of water, set up in a matter of hours by a large convective storm. Many automobile related deaths in a flash flood are in 2 feet of water due to the buoyant lift and current of the water.

In 1997, in Antelope Canyon a flash flood took 12 hikers, tumbling them down the canyon as helpless on lookers could only watch. A wall of water builds due to steep topography, channeling the water and striking a particular area in a thunderstorm.
In Big Thompson Canyon, Colorado in 1976, a thunderstorm remained stationary in the canyon for four hours. The topography fed the flash floods and carried many hikers and tourist down the canyon to their death. Many survived by fleeing their cars and climbing to safety, seeking shelter along the canyon walls. Those who chose to stay with their cars were swept away in the flood and died. The weight and proximity of the vehicle couldn’t allow them to achieve the safety they required.

Regional Flood; different from flash floods, regional floods inundate an area with rainfall over several weeks, causing fewer deaths and often more damage. Occurring in areas of large river valleys and low topography, these heavy rains often result due to cyclonic systems. Their can be many contributing factors as to why a particular river may flood; geological age, riverbed (shape & depth), damming (ice or natural materials), as well as the surrounding landscape.
The Hubbard Brook experiment[1] in 1963, illustrates clearing surrounding vegetation of a river valley, doesn’t allow for natural absorption. The excess water then creates floods further up or down the river valleys.

Are the causes the same? Are the effects the same?

In a sense no, while they are both rainfall cause by low-pressure systems. A regional flood occurs over a prolonged rainfall lasting several days or intense rainfall over a short period of time. A regional flood can be the result of ice or debris jam causing a river or stream to overflow. Melting snow can combine with rain in the winter and early spring, a severe thunderstorm can bring heavy rain or tropical cyclone can bring intense rainfall to the coastal and inland states. Where as a flash flood can occur within six hours of rainfall, after a dam or levee failure, following a sudden release of water held by ice or a debris jam. Flash floods can catch people unprepared. There is not always a warning to these deadly floods.

The effects of a flood are much more devastating, as they are intense rains within a very short period of time with little to no warning. A regional flood can be seen on radar and forecasted with time for preparation.

2. Will we be able to control the Mississippi River in the future? Evaluate the possibilities and potential problems. Discuss the effectiveness of some of our most common mitigation techniques, for example, levees and dams.

According to many sources, the Mississippi is an ecological treasure and an economic powerhouse, providing clean water and navigation. I believe the corps of engineers will try their best to control the river for as long as possible. However, as we’ve seen throughout our text, we can’t expect to control natural forces. The Mississippi is a very powerful natural source. The constant drudging to remove sediment and channeling will never change the instability of the river.

As sediment is deposited from its adjoining river systems, raising the riverbed floor, bringing the water over the levees and dams. In the lowest portion of the river, the average water flow is 645,000ft3/sec. We see evidence of levee and dam failure dating back to 1882, killing hundreds if not thousands of people since the commencement of mitigation.

When the levees and dams failed in 1973, the Mississippi flooded ten states. In 1993, the flooding of the Mississippi caused record flooding in 9 states, killing 48 people, submerging 75 towns, destroying 50,000 homes, closing 12 commercial airports and four interstate highways.

This ecological treasure and economic powerhouse is costing the US taxpayers a lot of money! Total cost for damages in 1993 alone was 12 billion dollars. The problem is human interaction is obstructing natures natural course. As evidenced throughout our course material, human interaction regularly causes more damage in dollars and to the environment than actually helping. The river grows as it ages, if the river had been left alone in the 1700 and 1800’s it would have cut its new path and dug its new riverbeds. With our current condition of controlling the Mississippi, more homeowners have moved closer to the river, relying on the dams and levees. As populations grow, we can only expect the damages from future failures to increase the death toll and cost of the catastrophes. Allowing the river to resume its normal course at this time would be irresponsible. A perfect example of how human interaction has cost more then it has improved.

3. Write an equation that describes fire. If fire is a necessary element in some ecosystems, why is it included in the textbook as a type of disaster?

All disasters are necessary to our ecosystems and planet. Hurricanes mix water for the environment of the sea and atmosphere, in a cooling down action for the planet. Earthquakes are the result of the earth continuously rebuilding its outer crust. Volcanoes relieve built up energy, cooling down the core of the planet. Floods wash the shores and allow vegetation to prosper. Fire clears the brush allowing new growth. With new growth comes an array of new vegetation as well as an increased boost to the carbon cycle during the growing years of the new vegetation. In the rain forests there is ample moisture and decomposition of the decaying vegetation. However, in dryer climates the vegetation needs moisture and decaying vegetation takes much longer to decompose. Forest fires provide an instrument to vegetation growth and decomposition.

Fire is described as the photosynthesis reaction in reverse. Fires can burn the undergrowth, leaf litter, dead branches and trees on a forest floor. Carefully controlled fires are sometimes deliberately set to prevent buildup of flammable ground material in forests. Recycling nutrients, helping to maintain the productivity of a variety of forest ecosystems.

In a fire the flammable material is heated to a point of combustion. Breaking old chemical bonds between carbon and hydrogen. New bonds are formed resulting in the heat of the fire.

Fire and photosynthesis have the same equation only opposite to each other:
Photosynthesis; 6CO2 + 6H2 O + HEAT SOURCE FROM THE SUN > C6 H12 O6 + 6O2
Fire; C6 H12 O6 + 6O2 > 6CO2 + 6H2 O + RELEASED HEAT
While fire provides for the forest they are dangerous and disastrous to humans. As population growth continues, people have chosen their homes near and in wild lands, giving the fires a wonderful source of fuel. Homes have become the fifth category of fuel for forest fires.

4. How can a wildfire create its own wind? Discuss some of the methods of fire prevention. Why are some effective and others not?

Fire creates its own weather pattern; often times creating wind ten times stronger then surrounding winds. Dr. Terry Clark, senior scientist at the National Center for Atmospheric Research[2], has done extensive research on the wind patterns created by wildfires.
Fire creates its own weather pattern, which can be fed back into the fire, enabling the fire to spread. Wildfires have the ability to create large whirling winds similar to a tornado with the heat of the fire as the vortex. Which is how we often hear and see debris being thrown in a fire.

People cannot extinguish wild fires, the best we can hope to do is control the direction slightly. Eventually the carbon accumulation creates a low-pressure system, causing precipitation.

Fire prevention, understands the variety of fires and small fire controls, and if uncontrolled calls the fire department in all situations.
Electrical fires: cut the power, smother and throw water at the base or seat of the fire.
Liquid fires: Do not use water, cut the power if in an oven or using a power source as heat, and then smother the fire. Water will dilute the liquid fuel and increase the strength and area of the fire.
Organic Fires: Smother and use water aimed at the base or seat of the fire.

Prevention: If living near a forest fire area, build appropriately with fire resistant materials. Keep all brush and flammable materials removed from the property, as this may serve to fuel a fire and limit your evacuation time. If building in these areas keep all materials as melt resistant as possible. Many firefighters have been severely injured from melting pipes and I-beams. Build exteriors of homes with natural materials (i.e. stucco, clay and concrete); keep all debris and vegetation clear from the home by a minimum of thirty feet. If built on a slope keep all debris and vegetation distances even greater. To prevent sparks or embers of wildfires from entering your home, place screens over all attic, foundation vents and chimneys.

If living in a non-fire hazardous zone, understand fire and your fire department and post your address prominently. If living on a farm a good practice saving time and lives is to know your fire department and keep regular contact through multiple events. These practices have saved lives, livestock and farm vegetation.

A few additional tips: (Fires kill more people in the US then any other violent crime) ▪ When buying, building or renovating your home, buy fire resistant materials ▪ Clean gutters regularly ▪ Keep vegetation 10 feet from your chimney ▪ Remove dead limbs ▪ Store firewood and other combustibles away from your home, and keep the lid on your trashcan.
And always, always own and update your fire extinguishers, plan escape routes and practice. Understand the smoke will kill you before the fire and stay low to the floor.

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[1] Miller Jr, G. T., Spoolman, Scott E. Living in the Environment: Concepts, Connections, and Solutions, 16th ed.,(Belmont, CA: Brooks/Cole CENGAGE Learning, 2009)(pp. 28)

[2] http://science.howstuffworks.com/wildfire2.htm