Storm Hazards Flashcards
Tropical Storm
A violent rotating storm which occurs at the mid-latitudes
Tropical Storm Formation
Strong upward air movement draws water vapour from ocean surface
Air rises (convection) and cools- condensing= clouds
Condensing- latent heat- energy, powering storm to draw up more water
Thunderstorms combine to form a giant storm
Eye develops- winds >120km/h on eye wall
Storm gathers strength and energy from warm ocean
Why does a storm develop an eye?
As air rapidly descends in the centre
Where are the strongest storm winds found?
In the eye wall
What happens when a storm reaches land?
Energy cut off
Friction slows it down
4 Conditions Needed
Sea water warmer than 27°c
5° from equator to tropics
Atmospheric instability
Uniform wind direction in all levels
Why do storms need oceans?
Storms derive their moisture and energy here
Why can storms be formed at lower latitudes in the summer?
Because it’s hotter, meaning sea surface temperature increases
Why does there need to be atmospheric instability?
Warm air forced to rise
Why’s the rotation of the earth important? (Coriolis Effect)
A certain amount of ‘spin’ is needed to initiate the rotation of a storm
Not strong enough at the Equator
Why does there need to be a uniform wind direction at all levels?
As different wind directions at different altitudes prevents the storm from attaining height and intensity
4 Hazards associated with storms
High winds (300km/h)
Storm surge (>3m)
Coastal / River flooding
Landslides
Effects of high winds
Destroy buildings
Uproot trees
Carry debris + smash it into other objects- injures + disrupts transport
Damages communication networks- fires + power cuts
What causes storm surge?
Intense low atmospheric pressure and powerful surface winds- creating high waves
Effects of storm surge
Floods in low lying areas
Freshwater pollution
Destroys homes and infrastructure
Agricultural land inundated with water- useless
What causes river flooding?
Warm, humid air generating torrential rainfall
Effects of flooding
Death
Flash floods in urban areas
Damages homes and infrastructure
What causes landslides?
Intense rainfall increasing pore water pressure
Weakens cohesion, triggering slope failure
Effects of landslides
Deaths
Destroys homes and infrastructure
Factors Affecting Impact of a Storm
Intensity Speed it travels through an area Distance from sea Warnings and response Preparation Physical geography
What’s the Saffir- Simpson Scale based on?
Wind speed and storm surge
1-5, estimates damage
Advantages of Saffir- Simpson Scale?
Straight forward
Easy comparison
Widely used
Disadvantages of Saffir- Simpson Scale?
Limited value when assessing impact
Doesn’t include rainfall
Doesn’t think about area affected i.e. pop density
Why is river flooding worsened in urban areas?
Impermeable surfaces
Drains
High building intensity
How can people prepare for a storm?
Insurance Minor property improvements Warnings given Emergency services trained Florida: evacuation routes clearly signposted
How can the effects of some storm hazards be prevented?
Can’t prevent the storm
Sea wall can reduce storm surge impact
Adaptation: Land use zoning
Coastal strips are used for recreation
Property behind
Adaptation: Adapting home functionality
Homes built on stilts
Homes have a garage at the bottom
-Means nothing valuable destroyed
Examples of Mitigation
Insurance
Structural responses
