Hazards (Storm Events)

Question 1

Distribution of tropical storms

Answer 1

Tropical maritime areas between 5-20 N/S but not on the equator.

Question 2

Distribution of hurricanes

Answer 2

N Atlantic (11% of storms) and NE Pacific (17% of storms)

Question 3

Distribution of cyclones

Answer 3

S Pacific/Indian (8% of storms). Off of Madagascar (11% of storms)

Question 4

Distribution of typhoons

Answer 4

NW Pacific (33% of storms)

Question 5

Distribution of willy willies

Answer 5

NW and NE of Australia (20% of storms)

Question 6

Conditions needed to form a tropical storm

Answer 6

• Ocean above 27C
• Water levels at 70m below surface
• At least 5-20 N/S of Equator for Coriolis effect
• Low level convergence

Question 7

Why do storms decay upon reaching land?

Answer 7

• Lose the source of heat and moisture

- Increased frictional drag decreases speed of storm

Question 8

Four stages of tropical storm formation

Answer 8

• Tropical Disturbance: <23 mph
• Tropical Depression: 23-39 mph
• Tropical Storm: 39-73 mph
• Hurricane: 74 mph +

Question 9

Scale used to measure tropical storm magnitude

Answer 9

Saffir Simpson Scale

Question 10

Four factors measured by the SS scale

Answer 10

• Central pressure
• Wind speed
• Storm surges
• Damage potential

Question 11

Frequency of tropical storms

Answer 11

• N Hemisphere: June-November
• S Hemisphere: November-April
• Frequent but few major hazards

Question 12

Regularity of tropical storms

Answer 12

Irregular- Occur in some areas but no clear pattern

Question 13

Predictability of tropical storms

Answer 13

Fairly predictable with satellite tracking of cloud formations.

Question 14

Primary hazards of tropical storms

Answer 14

• Strong winds
• Heavy rainfall
• Storm surges

Question 15

Secondary hazards

Answer 15

• Flooding

- Landslides

Question 16

Formation process of tropical storms

Answer 16

• Solar radiation heats the ocean to 27C. ITCZ is usually overhead
• Warm air rises and creates an area of low pressure
• This air cools as it rises and condenses. Forms cumulonimbus clouds and heavy rainfall
• Coriolis effect causes the air to spin upwards around a central eye
• Air rushes in from high pressure areas, replacing rising air and creating strong winds
• Cold air sinks in the eye of the storm
• Carried across the ocean by prevailing winds, building with evaporated water
• When it meets land it’s no longer powered by moisture and slows from friction with the land.

Question 17

Storm surges

Answer 17

Rising air creates low barometric pressure, and therefore an area of localised sea level rise. Winds create larger onshore waves and push a surge of water inland.

Question 18

Factors increasing severity of storm surges

Answer 18

• Low relief of coastal areas
• Funnelled coasts
• Storm track
• Intensity of storm
• High tide

Question 19

Short term responses to storms

Answer 19

Search & Rescue. Evacuation.

Question 20

Long term responses to storms

Answer 20

Mitigating the impacts of future storms. E.g. prevention, protection, prediction and preparedness

Question 21

Methods of prediction for storms

Answer 21

• Geostationary satellites
• Land and Sea based monitoring (NOAA)
• Aircraft reconnaissance

Question 22

Method of prevention of storms

Answer 22

Cloud seeding

Question 23

Methods of protection for storms

Answer 23

• Strengthening homes e.g. barricades
• Cyclone/hurricane drills
• Land use planning to reduce access to high risk areas
• Sea walls and flood defences to reduce storm surge risk
• Emergency service drills
• Insurance