Natural Disasters Weather vs Climate Natural Disasters Meteorological

Natural Disasters • Weather vs Climate • Natural Disasters • Meteorological • Climatological • Geological/Geophysical • Hydrological • Extraterrestrial • Biological

Weather vs Climate • Weather – Local atmospheric conditions at a given time – Atmosphere: layer of gases and particles surrounding and protecting Earth – Normal: everyday conditions – Severe: relatively rare, dangerous conditions

Weather vs Climate • Climate – Long-term weather – Averages and extremes

Natural Disasters • Events caused by natural processes • Severe property or environmental damage • Loss of life

Natural Disasters • 6 categories – Meteorological (weather) – Climatological (climate) – Geological/geophysical (Earth) – Hydrological (water) – Extraterrestrial (outer space) – Biological (life)

Meteorological • • • Thunderstorms Tornadoes Hurricanes Blizzards Ice storms Hailstorms

Thunderstorms • Result of air movement Stop at 3: 11 • Recall: Rising air (updraft) forms clouds • Clouds can build up until they become cumulonimbus clouds – Towering: 10 km (33, 000 ft) or taller – Made of mostly liquid water – Ice crystals form at the top – Responsible for thunderstorms

Thunderstorms • Precipitation falls through cloud, carrying air with it • Air radiates out from bottom of cloud as wind

Thunderstorms • Lightning: – Liquid (rising) and frozen (falling) droplets collide – Frozen droplets pull electrons off liquid droplets – Creates charge difference between top (positive) and bottom of cloud (negative) – Charge needs to be released lightning – Cloud-to-ground: positive charge builds up on Earth’s surface beneath cloud

Thunderstorms • Thunder – Caused by lightning – Lightning heats up air • Up to 50, 000 o. F (27, 760 o. C) – 5 x hotter than the Sun’s surface – Tube of air around lightning expands and contracts, causing vibration – Vibration = loud thunderclap – Vibrations continue, getting progressively smaller = rumbling

Thunderstorms • Dangers – Aircraft - turbulence – Heavy winds and rain – Hail – Lightning strikes – Flooding – Tornadoes

Tornadoes • Spinning columns of air • Most destructive natural disaster • Winds: 400 kilometers (250 miles) per hour or more • Formation – Ascending warm air is trapped under a layer of cold air – Can’t descend because air below it is too dense – Air molecules keep moving, forming a funnel cloud

Tornadoes • Warnings – Greenish or very dark sky – Large hail – Funnel cloud – Loud roar like a train • Dangers – High winds

Hurricanes • Also called typhoons or cyclones • Low pressure areas that form in tropical seas • Collect winds • Winds rise in tube shape, warm air descends in center of tube (eye) • Move out of tropical seas and keep pulling in winds

Hurricanes • Average diameter: 600 km (375 mi) • Wind speeds: 119 km (74 mi) per hour or more • Categories – 1: 119 -153 km/hr (74 -95 mph) – 2: 154 -177 km/hr (96 -110 mph) – 3: 178 -208 km/hr (111 -129 mph) – 4: 209 -251 km/hr (130 -156 mph) – 5: ≥ 252 km/hr (≥ 157 mph)

Hurricanes • Dangers – High winds – Flooding – Storm surge – Tornadoes

Blizzards • Snow formation – Ice crystals in clouds combine – Snow falls at <2 o. C (35. 6 o. F) • Blizzard: intense winter storm with winds ≥ 56 km/hr (35 mph)

• Dangers Blizzards – High winds (can reach hurricane speeds) – Snow accumulation – Cold – Flooding Thundersnow Start @2: 04 Stop @4: 11

Ice storms • Ice formation – Snow melts as it falls – Becomes freezing rain in colder air beneath clouds – Freezing rain falls through layer of subfreezing air ice • Dangers – Ice accumulation

Hailstorms • Hail formation – Forms in thunderstorms – Updrafts carry water droplets into very cold parts of the atmosphere – Droplets freeze and combine with one another – Size: ¼ in to >4 in • Dangers – Property damage – In combination with winds: personal injury

Climatological • Drought • Extreme heat • Wildfires

Drought • • Long-term low rain/snowfall Water body reductions Low water availability Dangers – Agricultural disasters – Danger to animals and plants – Danger to environment – Water contamination – Wildfires

Extreme Heat • Long-term high heat and/or humidity • High pressure dome heats up upper atmosphere and traps air near ground • Ground-level air heated up by Earth’s surface • Dangers – Health problems/death – Environmental/agricultural damage – Wildfires

Wildfires • Uncontrolled fires in natural areas • Dangers – Injury and death: animals and plants – Damage and destruction: structures – Air pollution – Soil structure weakening floods/landslides

Geological/Geophysical • Due to plate tectonics and underground processes • Earthquakes • Volcanoes • Landslides/avalanches • Sinkholes

Earthquakes • Shaking ground • Unpredictable • Tectonic plates slide past each other and get stuck • Energy built up is released when they slip apart

Earthquakes • Fault: cracks in crust between rock masses • Energy released as a seismic wave • Focus: point of energy release within Earth’s crust • Epicenter: point on surface above focus • Dangers – Property damage – Personal injury/death – Tsunamis

Volcanoes • Vents in Earth’s crust • Molten magma escapes at vents as lava

Volcanoes • Occur at subduction zones, divergent plate boundaries, and within plates – Subduction zones: lower plate melts and rises, mixing with gases and exploding through surface – Divergent boundaries: rift volcanoes • Magma ascends into space left behind when plates move apart • Less explosive

Volcanoes • Occur at subduction zones, divergent plate boundaries, and within plates – Within plates: hotspot volcanoes • Column of magma ascends from deep within mantle • Magma pushes up through crust • Plate continues to move, resulting in chain of volcanoes (e. g. Hawaii)

Volcanoes • Dangers – Explosive eruptions • Burning lava • Hot cinders • Ash • Other flying debris – Lava flows

• Dangers Volcanoes – Pyroclastic flows • Masses of ash, gas, and other materials • Hot: 100 -700 o. C (212 -1300 o. F) • Fast: 160 km (100 mi) per hour – Gas clouds – Ash accumulation – Tsunamis

Landslides/Avalanches • Earth, rock, ice, snow, and/or other debris moving down a hill or mountain • Triggered by ground movement (e. g. earthquake, volcano), heavy rainfall, erosion, or human intervention • Landslides: earth, rock, mud • Avalanche: ice, snow

Landslides/Avalanches • Dangers – Destruction of natural environments/human communities – Can bury animals (including humans)

Sinkholes • Sunken ground • Depth: <0. 3 m (1 ft) to >30 m (100 ft) • Crust beneath the surface gets hollowed out – Usually due to groundwater erosion • Dangers – Property damage (i. e. can swallow entire buildings) – Personal injury/death

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Hydrological • Tsunamis • Floods • Limnic eruptions

Tsunamis • Massive, rapidly moving waves • Caused by water displacement at sea – Earthquake – Volcano – Landslide – Meteorite strike • Size: >30 m (100 ft) high • Speed: up to 900 km/hr in open ocean

Tsunamis • Dangers – Force of water: property damage, injury, death – Drowning – Wash away soil – Displace animal communities – Flooding – Soil and water contamination – Fires

Floods • Water inundation on normally-dry land • Second-most destructive natural disaster • Few inches to tens of feet in depth • Four types – Overbank – Flash – Coastal – Ice jam

Floods • Overbank – Usually due to excess rain or snowmelt causing a body of water to overflow its banks – Covers floodplain (surrounding land) – Typically slow and long-lasting • Flash – Occur in a matter of hours – Average speed: ~3 m/s (9 ft/s) – Can move heavy debris (~100 pounds)

• Coastal Floods – Effects of tsunamis and hurricane storm surges – Can be fast and cover large swaths of land • Ice jam – Chunks of ice dam a water body – Water piles up behind ice and overflow banks – Jam breakage leads to flash floods downstream

Floods • Dangers – Destruction – Wash away soil – Water and soil contamination – Litter and debris left behind – Mold – Water-borne diseases

Limnic eruptions • Rare (only 2 recorded) • Deadly • Explosions of lakes formed in dormant volcanic craters in areas with relatively consistent temperatures • Gases leak from magma into lake floor • Lake water traps gases • Temperature changes would allow mixing and gas release at surface

Limnic eruptions • Gases build up • Lake disturbance (e. g. landslide) causes gases to explode upwards • Dangers – Cloud of poisonous gas widespread animal death

Extraterrestrial • Meteorite/asteroid impacts • Solar storms

Meteorite/Asteroid • Space rock that hits the Earth • Dangers – Widespread destruction (much like a nuclear bomb) – Air pollution – Sun blockage due to debris – Mass extinction (e. g. likely what caused the dinosaur extinction)

Solar Storms • Explosions on the surface of the Sun • Energy and magnetic waves from solar storms can reach Earth • Dangers – Electric grid and satellite disruption/damage – Solar radiation (especially dangerous for astronauts in International Space Station)

Biological • Epidemics/pandemics • Animal infestations

Epidemics/Pandemics • Unusually high spread of infectious disease – Contagion – Vector-borne • Epidemic: population-, community-, and/or regional-level • Pandemic: larger region, such as a continent, or worldwide

Epidemics/Pandemics • Dangers – Widespread illness/death • Examples – Avian flu – Cholera – Ebola – HIV/AIDS – Malaria

Animal Infestations • Widespread immigration or proliferation of animals that affect humans, other animals, crops, and property • Dangers – Property damage – Agricultural disasters – Environmental damage – Disease – Native species declines