Wildfires/Disease

Question 1

Describe the Fort McMurray wildfire in 2016.

Answer 1

May-July, 2016
Hot dry air mass, strong sustained winds
3200 buildings destroyed
9.9 billion in damages
2 indirect deaths

Question 2

What were the two major wildfires in Summer 2013 in the U.S. Southwest?

Answer 2

1. Black Forest Fire - Colorado, most destructive in Colorado’s history, 2 deaths, destroyed 500 homes
2. Wildfire Near Yarnell, Arizona - Swift-moving, destroyed 200 homes, 19 deaths (firefighters)

Question 3

Why are wildfires one of natures oldest phenomena?

Answer 3

Trees spread all over land, then grass evolved, then increase in charcoal in sediment made it worse

Before humans, wildfires would naturally put themselves out

Question 4

What is the process of wildfires?

Answer 4

They’re self-sustaining, rapid, high-temperature biochemical oxidation reactions.
Releases heat, light, etc.
Requires fuel, oxygen, and heat
Plants and other materials are broken down by combustion

Question 5

What are the most abundant gases released in fire?

Answer 5

Water vapour and carbon dioxide

Question 6

What is the fire triangle?

Answer 6

Oxygen, heat, fuel.

Question 7

What are the three phases of a wildfire?

Answer 7

1. Preignition
2. Combustion
3. Extinction

Question 8

What is the first phase of a wildfire, preignition?

Answer 8

Fuel achieves temperature and water content favourable to ignition.
Process #1: Preheating; fuel loses water, compounds are easily vapourized
Process #2: Pyrolysis; “heat divided” - split up carbon chains, processes that chemically degrade fuel, products include volatile gases, mineral ash, tars, etc.
The HEAT radiating from the flames causes BOTH preheating and pyrolysis in advance of the fire; these processes produce the fuel gases.

Question 9

What is the second phase of a wildfire, combustion?

Answer 9

Begins with ignition; doesn’t always make wildfires, unless sufficient fuel must be present.
Ignition is not a single process, but occurs repeatedly as wildfire moves.
Flaming combustion dominates early fire, is rapid and high temperature conversion of fuel to heat, characterized by flames and large amount of unburned material.
Smoldering combustion takes place at lower temperatures and doesn’t require pyrolysis for growth.

Question 10

What 3 proceesses control the heat transfer in wildfires?

Answer 10

• Depends on TOPOGRAPHY and WIND DIRECTION
• Transfer heat primarily through CONVECTION (radiation, which generates heat, also plays a role)
• Convective and radiant heat increases surface temperature of fuel
• Gases become less dense and rise
• Rising gases remove heat and combustion products from zone of flaming
• Pulls in fresh air to sustain combustion

Question 11

What is the third phase of a wildfire, extinction?

Answer 11

The point at which combustion, including smoldering, ceases. There is no longer heat and fuel to sustain the fire.

Question 12

What are the components of the fire environment?

Answer 12

Fuel, topography, and weather.

Question 13

What is the first component of the fire environment, fuel?

Answer 13

Complex; differs in type, size, quantity, arrangement, and moisture content.
Includes leaves, twigs, decaying material, grass, shrubs, etc.
Fuel size affects ignition and movements.
LANDSLIDES, HURRICANES AND TORNADOES can arrange debris to facilitate fires.

Question 14

What natural disasters can largely contribute to wildfires?

Answer 14

Landslides, tornadoes, and hurricanes can arrange debris to facilitate fires.
DROUGHT can dry out organic materials that then become fuel.

Question 15

What is the second component of the fire environment, topography?

Answer 15

Has a profound effect on fires; fuel moisture content is affected by LOCATION.
Drier fuels are found on south-facing slopes in Northern Hemisphere, and slopes exposed to PREVAILING WINDS.
Wildfires preheat fuels UP-SLOPE, making it easier to spread than down-slope.

Question 16

What is the third component of the fire environment, weather?

Answer 16

Has a dominant influence on wildfire, esp. temperature, precipitation, humidity, and wind.
Fires are common following DROUGHTS; can bring “dry thunderstorms” where lightning starts a fire, but the rain evaporates and cant extinguish them.
Low humidity = more fire burn
Wind direction = preheating unburned materials
Wind = carring embers to ignite spot fires

Question 17

What are the types of fires? How are they classified?

Answer 17

There’s GROUND fires, SURFACE fires, and CROWN fires.
Classified according to the layer of fuel that is allowing the fire to spread.

Question 18

What are ground fires?

Answer 18

Creep along underground surface. Less flaming, more smoldering.
They burn in duff; decaying organic matter in the soil, drained or temporarily dried out swamps, and in thicker peat deposits below the soil.

Question 19

What are surface fires?

Answer 19

Move along the surface with varying intensities.
Burn slowly with smoldering, but limited flaming. Burn grass, shrubs, dead/downed limbs, leaf litter, debris.

Question 20

What are crown fires?

Answer 20

Flaming is carried via tree canopies. Driven by strong winds and steep slopes.

Question 21

Which geographic regions are at risk from wildfies?

Answer 21

Areas near grasslands, woodlands, shrublands, or tundra are at risk during drought.
Large wildfires are most common in Alaska, Canadian Rockies, and from the Yukon Territory -> Lake Superior -> Labrador

Question 22

What are the effects of wildfires?

Answer 22

Burn vegetatoin, release smoke into the environment, char soil, create conditions for landslides, increase erosion and runoff, and harm wildlife.

Question 23

Extremely hot fires may leave a _____-_______ ___________ layer in the soil

Answer 23

water-repellant hydrophobic

Question 24

How do the effects of wildfire differ on different geologic environments?

Answer 24

Differing effects depend on type and moisture content of the soil and the duration and intensity of the fire.

Question 25

How is climate change affecting wildfires?

Answer 25

Changes in temperature, precipitation, and frequency/intensity of severe storms can make wildfires worse/more prevalent.

Question 26

How does wildfire negatively affect vegetation, animals, and humans?

Answer 26

Vegetation: Kills it, can make plant vulnerable to later destruction or disease or drought.
Animals: alters habitats, changes who survives.
Humans: affects our water quality (increase in erosion), smoke and haze can make eye, respiratory, and skin problems, destroys personal property.

Question 27

How does wildfire positively affect the environment/plants/animals?

Answer 27

Environment: leaves an accumulation of carbon and increases nutrient content of soil, reduces populations of microorganisms (parasites, diseases)
Plants: decreases competition for resources, stimulates flowering, removes surface litter for grass, recycles nutrients in system
Animals: creates new habitats in burnt logs, more plant life

Question 28

What are the primary approaches to minimizing wildfire hazard? AKA Fire management?

Answer 28

Science, education, data collection, use of prescribed burns.

Question 29

What is science and education in the fire management process?

Answer 29

Understand the fire regime for an ecosystem; types of fuel availanble, fire behaviour, overall fire history.
Educate people that wildfire is a hazard and how to reduce their risk.

Question 30

What is data collection and prescribed burns in the fire management process?

Answer 30

Data collection: remote sensing, mapping vegetation and potential fuel, moisture content, Fire Potential Index (FPI) maps.
Prescribed Burns: controlled burns to manage forests; a way to counter dangerous buildup of fuel from suppression; reduces fuel for more catastrophic fires; MUST HAVE A WRITTEN PLAN TO CONTROL IT

Question 31

Insurance gives people living in wildfire-prone areas a ________ ________ of ________.

Answer 31

False sense of security.

Question 32

What are some adjustments to the wildfire hazard?

Answer 32

• Codes and regulations
• Fire insurance
• Evacuation

Question 33

Prepare _______, survive ________, be safe _______.

Answer 33

Prepare NOW, survive DURING, be safe AFTER.

Question 34

DISEASE

Answer 34

TIME

Question 35

What are large-scale diseases described as?

Answer 35

Epidemics, pandemics, or plagues.
They affect human populations most directly.

Question 36

Disease can spread around the world as long as there are _______ to infect.

Answer 36

Hosts

Question 37

What is the difference between outbreak, epidemic, pandemic, and endemic?

Answer 37

Outbreak: simultaneous, related occurrence of several cases.
Epidemic: uncontrolled outbreak of communicable (infectious or contagious) disease.
Pandemic: international or wide-travelling simultaneous epidemics of the same conditions.
Endemic: means that the pandemic will not end with the virus disappearing; it’s hoping that enough people will gain immunity from the virus and transmission/death will be reduced, even as the virus continues to circulate. Very optimistic.

Question 38

What are the types of epidemic spread?

Answer 38

Common-Vehicle or Source Epidemic: when a disease is spread by a pathogen from a single or common source, such as contaminated water, in the case of cholera or E-coli.
Propagated Epidemic: the disease is transmitted by an infectious agent. E.g., person-to-person contact, or human to animal and back to human (malaria, corona viruses)
Vectors: Animal agents that can transfer the disease from one host to another. Can be insects, rodents.

Question 39

How does the SPREAD of disease occur?

Answer 39

a) if the population is not immune and includes carriers, and b) if susceptibility to disease increases through conditions such as malnutrition.

Question 40

How does the TRANSMISSION of disease increase?

Answer 40

a) physical events, such as sewer/water main rupture result in fecal contamination
b) lack of routine programs of disease control which spread endemic diseases such as cholera
c) overcrowding in refugee camps which increases human contact and poor sanitation

Question 41

What was the Spanish Flu?

Answer 41

• Influenza Pandemic from 1918-1919
• Killed 40 million people, 5x as many as WWI
• Globally spread by soldiers
• Mortality was 20-28%
• Found in isolated communities, suggesting that it could be spread through the atmosphere, increasing its ability to spread globally at a quick rate

Question 42

What was the Bubonic Plague/Black Death?

Answer 42

• Spread by rodents completing a cycle of bacillus spread from fleas, to rats, to humans
• Swelling of lymph notes, infection, and pneumonia leading to fever, delirium, vomiting, bleeding, and finally death
• STILL found around the world, with 650 documented cases/year and 120 deaths/year.
• 3 Major pandemics: 542-546 AD, 1347-1350 AD, and in 1894.

Question 43

What is the Flu (Influenza)?

Answer 43

• A virus
• It is unpredictable in its severity, mortality, and pattern of spread
• Rapid surge with an exponential increase that overcomes a population’s capacity to cope
• Occurs in waves with increasing severity and different targets

Question 44

What are structural responses to disease?

Answer 44

• Design facilities to provide medicinal support to victims
• Design refugee camps to limit spread and don’t overcrowd them

Question 45

Why are refugee camps sometimes responsible for the spread of disease in the first place?

Answer 45

• Close exposure in crowded areas = contagious
• Limits on food and services = weak immune systems
• Sanitation is not good; bad disposal of sewage, no access to clean water, etc.

Question 46

What are some methods of planning and policy on preventing disease?

Answer 46

Keep students home when ill, promote good hygeine, good cleaning and ventilation procedures, reduce crowding.