Extreme Weather Notes
WHAT IS WEATHER?
 Describes the state of the air at a particular place & time.
 Takes place in the troposphere (6-20km)
CLIMATE=WEATHER?
 Is NOT to be mistaken as the same thing!
 Climate is the condition of the atmosphere over a large area over the years.
 Weather is in a specific place at a specific time.
EXTREME WEATHER
 Weather phenomena that are at the extremes of the historical distribution, especially severe or
unseasonal weather.
CAUSES OF EXTREME WEATHER
There are several different factors that can cause extreme weather.
Some of them include:
 The angle of the earth’s axis
 Deforestation
 Wind patterns
 Carbon emissions
 Volcanic eruptions
EFFECT OF CLIMATE CHANGE ON EXTREME WEATHER
Climate change will do several things to the weather:
 Certain areas get hotter or colder
 Creating more wind
 Extending and diminishing seasons
 Erratic precipitation
 All of these circumstances enable more and worse extreme weather events.
KINDS OF EXTREME WEATHER
 Hot/Cold Waves
 Floods
 Tornadoes
 Droughts
 Monsoons
 Blizzards
 Hurricanes
1. HEAT WAVES/COLD WAVES
Heat waves: A long time of very high temperatures
 No definition for heat waves, it happens all over the world and differs in temperature (i.e. if the
Yukon had a heat wave it would greatly differ from Africa having a heat wave)
 Very hot and high levels of humidity causes relative temperature to increase to dangerous levels
 Not visible
 Has severe effects such as, death of livestock and wildlife
 Effects directly affecting the human population are: dehydration, heat cramps, heat expansion,
heat stroke
 Soil dries out making it hard to cultivate land for agriculture
 More frequent breaks of wildfires due to dryness of the land
 Lakes, rivers, ponds, oceans being dried up as well
 Power outages due to the demand of electricity
Cold Waves: Rapid fall in temperature within 24hr
 Causes death of livestock and wildlife
 Exposure to freezing temperatures makes it hard for animals to get the food needed causing
them to die of starvation or hypothermia
 Freezes water pipes
 If water main breaks water become hard to maintain (this makes firemen’s jobs very difficult)
 Use of electrical heating rises
 Fires are VERY dangerous
 Transportation gets very difficult due to motors of vehicles freezing
 Canada and Siberia receive very cold weather
 Breathing air is dense (more oxygen)
 Winter in Canada greatly differs from Australia’s but a big decrease from the normal
temperature in Australia are just as destructive
 Year without summer 1815 random cold periods in summer due to volcanic eruption
2. FLOODS
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HUGE overflow of water that covers land
Water escapes its usual home
Can occur in any form of body of water
Occurs when water expands so much it has no were else to go but nearby villages or cities
Damage to houses, businesses can be eliminated by moving away from bodies of water
but living nearby to water for some people is the only way of work, food and shelter
Damage to all types of buildings
Decrease in population due to drowning
Clean water mixes with dirty flood water resulting in no drinking water
Water diseases
Crop and food significantly decrease
Trees and plants die
Loss of property causes economic struggles
Dams, levees, bunds, reservoirs, weirs are used as precautionary tactics to maintain a
flood
If those fail sandbags and tubes are used
KINDS OF FLOODS:
 Riverine- Slow kinds: Caused by rainfall, fast snow melting, Excess rain from
monsoons,huricanes as well as blocked drains not letting water go anywhere else
o Fast kinds: Flash floods from thunder storms, breakage of a dam, landslide
 Coastal- Caused by sea storms or aftermath of a tsunami or hurricane
 Catastrophic- Caused by unexpected event
 Muddy- Caused by excess materials from crops mixed with water
BENEFITS:
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Recharges the ground/roots
Helps the soil for future growths
Waters down extreme dry areas
Creates new ecosystems
3. TORNADOES
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The most violent storm known to man
Only affects a small portion of land
Average deaths of 150/year
Average 12.8 million in property damage/year
Tornado is linked to a strong thunderstorm
70% of all tornadoes happen in the U.S
Usually occur in late spring or early summer but can happen at any time
min speed of 60mph max speed of 300mph
10 miles long, 100 ft wide
It’s path is very narrow but travels very fast
The magnitude of a tornado is measured on the Fujita scale
Shaped like a column (tube) with a cloud at the top
Travels a few miles before disintegrating
EFFECT ON HUMANS
 Weather plays an important role in how humans go about their daily lives
 Extreme weather has an even larger impact.
 In the case of hurricanes, tornadoes, and floods, extreme weather can destroy people’s
houses or even kill. (Ex. Hurricane Katrina in 2005 killed at least 1,836 and created an
estimated $81 billion in damages)
 Drought and dust storms can destroy crops ad bankrupt farmers. (Ex. In the 1930s during
the depression there was a huge drought in western North America in which no crops were
growing.)
STORM TRACKING AND MEASURING WEATHER
Storm tracking
 Meteorological centres use several different technologies to track the weather these include:
 Satellite imaging
 Pulse-Doppler radar [motion of precipitation]
 Rain gauge
 Weather vane [direction of wind]
 Anemometer [wind speed]
 Barometer [air pressure]
 Hygrometer [humidity]
 Scientists often send instruments up into the atmosphere using weather balloons to get more
accurate data.
Measuring Weather
 Each type of weather event is unique and so each is measured in a different way
 Volcanoes are measured with the Volcanic Explosivity Index [A scale of 1-8 based on volume of
debris and cloud, cloud height, and visual observations]
 Tornadoes are measured using the Fujita Scale [ranging from F0 (weakest) to F5 (strongest)
based on the damage the tornado inflicts on man-made structures and vegetation]
 Tropical cyclones (also called hurricanes or typhoons) are measured using the Beaufort scale [012 based on the speed of 10-minute sustained winds]
 Floods are measured in how many meters of water there are above the normal ground level
 Hail is measured by the average diameter of the hail stones
CONCLUSION 
There are many different kinds of weather and different places on the planet experiences different types
of weather based on a number of factors. All weather, regardless of the severity, impacts human society
and human society has an impact on the weather through our part in the changing climate.