Hurricanes

Question 0

Definition of Tropical Disturbance?

Answer 0

A discrete tropical weather system of apparantely organized convection, generally 200-600 km, nonfrontal

Question 1

Definition of tropical cyclone?

Answer 1

Non-frontal synoptic scale low-pressure system over tropical or sub-tropical waters with organized convection (i.e. thunderstorm activity) and definite cyclonic surface wind circulation

Question 2

Definition of Tropical Depression (TD)?

Answer 2

A tropical cyclone that has max sustained wind speed of 38 mph or less. A closed circulation.

Question 3

Definition of Tropical Storm (TS)?

Answer 3

When the tropical cyclone has max sustained wind reach 39-73 mph.

Question 4

Definition of Hurricane (H)?

Answer 4

When the winds exceed 74 mph.

Question 5

How a hurricane develops in 4 stages?

Answer 5

1. Tropical Disturbance
2. Tropcal Depression
3. Tropical Storm
4. Hurricane

Question 6

Describe the size of a hurricane.

Answer 6

About 300 miles wide, although it can vary.

Question 7

Describe what is an eye of a hurricane.

Answer 7

Located at the hurricane’s centre. Relatively calm.

Area approximately 20-40 miles across

Question 8

Describe the eyewall of a hurricane.

Answer 8

Surround the eye of a hurricane. Composed of dense clouds that contain the highest winds in the storm.

Question 9

Describe the environmental factors of TC genesis in 6 bullet points.

Answer 9

1. Large values of low-level relative vorticity (турбулентность).
2. A location at least a few degrees poleward to the equator, giving a significant value of planetary vorticity.
3. Weak vertical shear of the horizontal winds.
4. Sea-surface temperatures exceeding 26•C and a deep thermocline (температурный скачок).
5. Condition instability through a deep atmospheric layer.
6. Large values of relative humidity in the lower and middle troposphere.

Question 10

Describe the hazards caused by TC.

Answer 10

Tropical cyclones kill thousands and cause billions of dollars of property damage over oceans and land.
At the coast, the major impacts of a landfalling tropical cyclone are: storm surge (линевая волна), winds, rainfall, tornadoes, lightning.
Inland, the largest threats to life and property occur as a result of flash flooding and large scale riverine flooding from excessive rainfall.

Question 11

Describe what does the severity of hazard imapct depend on.

Answer 11

Spatial location of landfall.
Timing of landfall.
Length of time since last severe event.
Population vulnerability (related to preparedness, building design, accuracy of forecasting and warning)

Question 12

Describe Tropical Disturbance/Thunderstrom Cluster.

Answer 12

Warm, moist air rises and hits cold air. They merge into a cluster up to 300 miles wide. The area is at low pressure, contains cloudiness an precipitation with no strong winds. Heavy rain can occur.

Question 13

Describe Tropical Depression (TD)

Answer 13

There is a pressure drop in the center of the storm. Wind speed picks up (20-38 mph) and starts rotating in a pattern, and heavy rainfall begins.

Question 14

Describe Tropical Storm.

Answer 14

Evaporation and condensation intensify, rising warm air is trapped. Spinning increases due to Earth’s rotation, wind hits 39 mph.

Question 15

Describe the hurricane.

Answer 15

Billions of gallons of water evaporate and condense, fueling the storm. Warm, dry air in center forms the eye. Winds hit 74 mph. Average diameter is 300 miles

Question 16

What scale is used to measure and compare different stages of hurricanes? What does it measure?

Answer 16

Saffir/Simpson scale. Measures central pressure (mb), wind speed (mph), surge (ft), damage caused.