The Challenge of Natural Hazards: Paper 1 Section A: Weather Hazards Flashcards
(21 cards)
Air Circulation
-Air rises at equator (low pressure)
-Air sinks at 30N/S (high pressure) (moves along ground back to equator or poles)
-Air rises at 60N/S (low pressure) (moves back to equator or poles)
-Air sinks at poles (high pressure) (drawn back to equator)
Order of Cells from Equator to Poles
Hadley Cell
Ferrel Cell
Polar Cell
Air Circulation affecting Weather
-Equator: Warm, moist air rises and forms clouds so it rains a lot
-30N/S: Released most moisture to rain so is dry and little rainfall
-60N/S: Warm air rising forming cloud cover and rainfall
Tropical Storm Requirements
-Between 5 and 30N/S
-Sea 27 degrees min
-Low wind shear
How a Tropical Storm Forms
-Warm water evaporates and condenses into clouds, releasing huge amounts of energy
-Rising air creates low pressure, increasing surface winds
-Storm spins due to Coriolis
-As storm moves over ocean, energy from warm water strengthens storm so wind speeds increase
Features and Structure of a Tropical Storm
-Eye: centre of storm, up to 50km across, caused by descending air, low pressure, no rain, high temp
-Eyewall: very strong winds (160kph), storm clouds, terrential rain and low temp
-Edge of Storm: wind speeds fall, clouds are smaller and scattered, rain less intense, temp increases
Spin Direction in Different Hemispheres:
Northern: Anticlockwise
Southern: Clockwise
Typhoon Haiyan Stats
-Philippines
-8th Nov 2013
-Tacloban and Cebu worst affected (280mm rain and winds of 314kph)
-Storm surge waves up to 2.3m and a high tide meant Tacloban was hit with 5m tall waves
Typhoon Haiyan Primary Effects
-8000 people killed
-1mil homes severly damaged/destroyed
-1.9mil made homeless
-Damaged electricity lines
-Water supplies contaminated
-Flooded 600,000 hectares of farmland
-Cost of $13mil
Typhoon Haiyan Secondary Effects
-Flooding triggered several landscapes, blocking roads and delaying arrival of aid
-5.6mil workers lost jobs after businesses and agricultural land were destroyed
-Lack of clean water caused outbreak of diseases
Typhoon Haiyan Immediate Responses
-PAGASA broadcast warnings about Typhoon Haiyan 2 days before it made landfall (led to evacuation of 800,000 people)
-Fishermen warned not to go to sea
-Philippines declared state of emergency leading to charities offering aid
-Plan International constructed pit latrines for 100,000 people to help prevent spread of disease
Typhoon Haiyan Long Term Responses
-UN appealed for over $300mil to help fund rebuilding and relief
-Charities built new storm-resistant houses for those who lost their homes
-Philippines’ tourism board encouraged people to visit emphasising most areas were unaffected
Climate Change Affecting Tropical Storms
-Frequency: Oceans will stay 27degrees or higher for longer each year
-Distribution: Average ocean temp rises, more of the world’s ocean can be 27degrees or more
-Intensity: Higher sea surface temps likely to cause mor evaporation and increased cloud formation menaing more energy released
Reducing Effects of Tropical Storms
-Prediction and Monitoring: Computer models can predict storm’s path from monitoring and predict where and when a tropical storm will happen to evacuate people
-Planning: Future developments, Evacuation routes, Prepare emergency services
-Protection: Buildings on stilts and designed to withstand tropical storms, Flood defences along rivers
Weather Hazards in the UK
-Strong Winds
-Heavy Rainfall
-Snow and Ice
-Drought
-Thunderstorms
-Heat Waves
Weather in UK Becoming More Extreme
-Temperature: UK’s ten warmest years all occured since 1990, 2018 was joint hottest summer, 7 of UK’s 11 coldest temps occured since 1980, December 2010 was coldest month for over 100 years
-Rainfall: More rainfall records broken between 2010-2014 than in any decade, Major flooding events more frequent over past decade, December 2015 was wettest month ever in UK
Somerset Levels Flooding Stats
-Dec 2013 to Feb 2014, Sommerset experienced 3 times the average rainfall
-Lots of rain fell on already saturated ground, coincided with high tides and storm surges, causing extensive flooding in Somerset Levels
Social Impacts of Somerset Levels Flooding
-More than 600 homes flooded, and many people forced to evacuate
-Villages such as Muchelney were cut off by road, only way in or out was by boat
-Major transport links such as A361 and train lines were closed/disrupted
-Insurance prices soared, and some residents were unable to insure homes against future flooding
Environmental Impacts of Somerset Levels Flooding
-11,500 hectares flooded, including farmland, destroying many crops
-Standing water made ground toxic andd unproductive for over a year
-Loss of nutrients and damage to soil structure decreased long-term fertility of the land
-Tonnes of mud and debris were left by the floods, damaging vegetation
Economic Impacts of Sommerset Flooding
-Total cost of damage was estimated over £80mil
-Local companies lost more than £1.2mil in business
-Loss of tourism cost the county £200mil
Management Startegies to Reduce Flooding of Somerset Levels
-Warning systems
-Individuals and local authorities used sandbags and floorboards to try limit flood damage
-Turning temporary pumping stations into permanent ones
-Regular dredging of rivers Parrett and Tone
-Tidal Barrage at Bridgwater
-Widening River Sowy’s channel and King’s Sedgemoor Drain
