What are the Five Main Hazards of a
Thunderstorm?
L ightning
W ind (violent)
H ail
F loods
Tornadoes
Hail
- is precipitation in the form of balls or chunks
of ice.
- There are two reasons hail forms.
- the ice pellets keep growing until they are
too heavy for the updrafts to hold them up
and fall down to Earth.
Damage caused by hail:
-damage to crops
-damage to cars
Violent winds
Cause: Due to the cold downdrafts concentrating on a particular spot instead
of spreading out. This results in winds with speeds of more than 160km/h
-they are called downbursts when the downdrafts are concentrated in a small
area.
Macrobursts and Mircobursts
-depending on the size of area the downburst affect they are either classified as
macrobursts or microbursts.
-macrobursts cause destruction 5km wide and have wind speed over 200km/h and
last about 30 minutes.
-microbursts are even worse because they affect areas of less than 3km and have
winds exceeding 250km/h and last about 10 minutes. However since they are so
small it makes it harder to detect and prepare for them.
Floods
Cause:
- happens when a storm moves slowly over an
area causing the storm to dump too much rain on
one particular area.
-if the rain falls faster than the ground can absorb
it, or faster than streams and rivers can transport
out
Damage:
- Damage to property
- Could result in death
Lightning
Cause: It is
caused by the rapid
rush of air in a
cumulonimbus
cloud, which causes
static electricity
which creates
regions of opposite
charges.
Damage:
-causes fires,
human injuries and
deaths
Recurring Weather
What is recurring weather?
Droughts
Heat waves
Cold Waves
What is recurring weather?
Recurring weather is a weather pattern that takes
place over a long period of time.
Definition:
Droughts are
extended
periods of time
with well
below normal
rainfall.
Droughts
~Droughts are usually
the result of shifts in
global wind patterns
that allow high
pressure systems to
persist for weeks or
months.
~ A drought will occur until the global
patterns moves the high pressure
system out of the way and
condensation will start.
Damage:
Droughts can
cause the loss of
crops.
Heat Waves
Definition: are extended periods
of above normal temperatures.
~ When heat waves occur very
little clouds are formed if any
because condensation doesn’t
occur so you get the all of the
blazing heat.
~ The national weather
service routinely reports
the heat index (so people
know how hot it could get
as well as the humidity
level)
~ As the air under a high
pressure system sinks it
warms by compression
and causes above normal
temperature.
~ If air is humid the evaporation is
reduced making it more
uncomfortable on the human body
because it cannot correctly regulate
its internal temperature. ~ This
increases the odds of sunstrokes,
heart attacks and sometimes even
death.
~ Atmospheric railway is
what weather systems
follow is further north and
weaker during the summer.
This means the upper air
currents that might guide
the high pressure system
are so weak that if there is
a heat wave chances are it
won’t move for months.
Air Temperature (degrees Celsius)
Relative Humidity
Definition: A cold wave is the
opposite of a heat wave, it is an
extended period with below
normal temperatures.
~ Interestingly enough
cold waves are brought
on by the same high
pressure systems as heat
waves.
Cold waves
~ Because the
time of year and
location, winter
high pressure
systems are more
influenced by
atmospheric
railway then they
are in the
summer.
~ Because wind transports
heat away from the body,
the effects of cold air are
worsened by wind. This is
known as Wind-chill
factor.
~ However cold
waves are caused
by systems of
continental polar
or arctic origin.
~ Air near the poles is
colder, which causes it to
sink, creating a strong
high pressure system.
~ The wind-chill index measures the wind chill
factor which estimates the heat loss from the
human skin caused by the cold air and wind.