Hazards Flashcards
1
Q
What is a hazard?
A
- An event that threatens the well-being of people and their property
2
Q
What are the four categories of hazards?
A
- Biological
- Tectonic
- Atmospheric
- Geomorphic
3
Q
What is risk?
A
- The possibility of suffering harm or loss
4
Q
What ia natural disaster?
A
- A hazard produced by enviornmental processes, e.g. storms, floods, earthquakes and volcanic eruptions.
5
Q
What are the seven conditions needed to produce a tropical cyclone?
A
- Surface temperature 26C
- Warm water to depth of 70m
- Disturabnce in lower atmospheric circulation
- Large enough coriolis force to produce certain patterns of wind
- Unstable air with high humidity
- Rapid outflow of air at high level and inflow of air at low level
6
Q
How does a tropical storm form?
A
- Start when strong clusters of thunderstorms dift over warm ocean waters
- The very warm air fromt he strom and the ocean surface combine and begin rising creating low pressure at the surface
- Trade winds blowing in opposite directions cause the strom to start spinning and rising warm air causes pressure to decrease hgih altitudes
- Air rises faster and faster to fill this low pressure, in turn drawing more air off the sea and sucking cooler, drier air downwards
- As the stotm moves over the ocean it picks up more moist, warm air. Wind speeds increase as more air is sucked into the low pressure centre.
7
Q
Where are tropical storms found?
A
- Between 10 to 30 degrees Northa nd South of equator
8
Q
What are storm surges?
A
- Combination of low pressure near the centre and strong onshore winds, which results in large increases in sea levels.
9
Q
When are tropical storms classified as hurricanes?
A
- When their wind speeds are greater than 118 km/hr
10
Q
When do tropical storms dissipate rapidly?
A
- When they moe over cold water or over a large mass of land as they derive their energy from warm water and latent heat of condensation.
11
Q
What are the three distinct elements of a hurricane?
A
- Eye - region usually 30-60km in diamtere found in center of hurrican where skies are clear
- Eye wall - wall of cloud an thunderstomrs surround eye
- Spiral rainbands - bands of thunderstorms that spiral around the hurricane
12
Q
What are synoptic weather charts?
A
- Used to show a pressure map of depression or tropical storm
13
Q
What is the saffir-simpson scale?
A
- A scale made up of five categories distinguished by wind that is sustained and measured by its present intensity
14
Q
How does naming hurricane helps?
A
- improves communication, especially exhcaning detailed storm information between weather stations coastal bases and ships.
15
Q
What is mitigation?
A
- The action of reducing the severity of a hazard event