Hurricanes

Question 1

Regarding season, what is declination?

Answer 1

Latitude of the subsolar point.

Question 2

_____ energy drives the Earth-atmosphere system.

Answer 2

Solar.

Question 3

How does air circulate in Hadley cells?

Answer 3

Air cools and sinks, rising air is replaced, warm air rises.

Question 4

Wind direction and velocity are controlled by what four things?

Answer 4

Gravitation.

Pressure gradients.

Coriolis effect.

Friction.

Question 5

What is an isobar?

Answer 5

An “isoline” plotted on a weather map to connect points of equal pressure.

Question 6

What is the Coriolis effect?

Answer 6

Moving objecst seem to veer toward the right in the Northern hemisphere and left in the Southern hemisphere.

Question 7

What are tropical cyclones?

Answer 7

Rotating, organized system of clouds and thunderstorms that originate over tropical or subtropical waters and have closed circulation.

Question 8

Define the sustained wind threshold for tropical storms, hurricanes, and major hurricanes.

Answer 8

Tropical Storm: 63km/h

Hurricane: 119km/h

Major hurricane: 178km/h or higher.

Question 9

When is the season for Atlantic hurricanes?

Answer 9

June 1st - November 30th.

Question 10

Classification of hurricanes is based on what?

Answer 10

Saffir-Simpson Wind Speed.

Question 11

Damage from hurricanes can come in what four forms>

Answer 11

Flooding.

Winds.

Tornadoes.

Waves.

Question 12

Leading cause of hurricane associated death in the U.S.?

Answer 12

Storm surge, followed by flooding due to rain.

Question 13

Waves in hurricanes are driven by what? What are three potential consequences?

Answer 13

Cyclonic winds.

Beach erosion, rip currents, structure damage.

Question 14

Storm surge and torrential rains can cause flooding how far inland?

Answer 14

Storm surge: 1km.

Torrential rains: 100kms.

Question 15

What is a major consequence regarding infrastructure, given the increasing frequency of hurricane activity?

Answer 15

Coastal development at risk.

Question 16

What are six ways to combat coastal erosion?

Answer 16

Preserving coastal wetlands, dunes, reefs to absorb storm surges.

Replenishing beaches, improve infrastructure that affords coastal protection (e.g., seawalls).

Elevating vulnerable buildings to reduce flood damage.

Designing structures to be resilient to high winds, flying debris.

Policies that discourage development in vulnerable areas.

Preparing prior to storm’s arrival by boarding windows, clearing property of potential flying debris, evacuation plan.

Question 17

What are three required conditions for hurricane development?

Answer 17

Upper 60m of ocean has to be at least 27°C.

At least 500km from the equator (requires Coriolis effect).

Upper-level winds should be weak (low vertical shear).

Question 18

When do high wind shears occur? What is a consequence of them?

Answer 18

El Nino year.

Storm’s latent heat focused over larger area instead of small area.

Question 19

Hurricanes can evolve from tropical disturbances to tropical depressions. Define both of these, and how cyclonic rotation can change.

Answer 19

Tropical Disturbance: low pressure zone draws in clusters of thunderstorms, not fully organized.

Tropical Depressions: surface winds strengthen, flow more efficient around centre.

Cyclonic rotation can become counter-clockwise.

Question 20

Convergence of surface wind takes on what effect?

Answer 20

Chimney effect, warm moist air to stratosphere; winds spiral up core walls.

Question 21

During hurricanes, what three things does condensation of vapour entail?

Answer 21

Latent heat is emitted during condensation.

Increase in updraft.

Increased inward flow of surface winds.

Question 22

It is difficult to be certain of hurricane paths. Why is this?

Answer 22

They adjust to other high- and low-pressure systems.

Question 23

What are Cape Verde-type hurricanes?

Answer 23

Trade winds push cyclone to west, Coriolanus effect adds curve to right as it moves north; Bermuda High.

Question 24

What is the Bermuda High?

Answer 24

Part of the North Atlantic Oscillation (NAO); NAO strengthen or weaken over a decade.

Question 25

What are Caribbean and Gulf of Mexico-type hurricanes?

Answer 25

Form over waters of the Caribbean and Gulf of Mexico at the Intertropical Convergence Zone (ITCZ).

Question 26

What is the Intertropical Convergence Zone?

Answer 26

Where trade winds meet near equator.

Question 27

What are four elements used to help predict hurricane seasons?

Answer 27

Sahel region of Africa wet = more thunderstorms to nucleate a hurricane.

Warmer ocean temperatures = more energy for hurricanes.

Low atmospheric pressure in Caribbean region.

Conditions in the Pacific Ocean: La Niña in the Pacific Ocean moves hurricane over warmer water; El Niño in Pacific Ocean, winds break up cyclones.

Question 28

List three coastal mitigation strategies.

Answer 28

Groynes.

Breakwaters.

Sea walls.

Question 29

What building code mitigations can be taken?

Answer 29

Stricter codes.

Roof straps.

Wind blown debris.

Question 30

Why was Hurricane Katrina so devastating for New Orleans?

Answer 30

95% of it below sea level, 8.5m storm surge broke >50 levees and floodwalls, 85% flooded.

Question 31

Very intense cyclones have small _____.

Answer 31

Eyewalls.

Question 32

How do eyewalls form?

Answer 32

Outer rain bands strengthen, organize into a ring of thunderstorms, Forms an outer eyewall which moves inward. Takes needed moisture and momentum from inner eyewall.

Question 33

Strongest winds are at the _____, and a _____ can weaken the hurricane.

Answer 33

Eyewall; collapse.

Question 34

Loss of energy kills a hurricane. List three ways this occurs.

Answer 34

Moving into colder waters.

Shear winds at height reduce latent heat of condensation.

Moving over land cuts off supply of moisture.