Meteorlogical Causes Of Flooding

Question 1

What are the main causes of flooding?

Answer 1

Intense rainfall over a short period of time (flash flood)
Prolonged rainfall/ monsoons
Tropical storms
Snowmelt

Question 2

What does most of the flooding seen in the uk relate to?

Answer 2

Mid-latitude depressions that brings 2 fronts

Question 3

What 2 types of front does the uk experience?

Answer 3

Showers and rain occur with the passing of a warm front
Heavier rain falls with the cold front

Question 4

What are isobars?

Answer 4

Lines joining points of equal pressure similar to contours which are shown on weather charts

Question 5

How is pressure measured?

Answer 5

In Millibars

Question 6

How many Millibars is an isobar?

Answer 6

4

Question 7

What does a lower pressure mean on a weather chart?

Answer 7

A greater depression

Question 8

How can depressions be recognised?

Answer 8

An area of closely spaced isobars often in a roughly circular shape where pressure is lower than the surrounding area

Question 9

Where is the lowest pressure in a depression?

Answer 9

The middle

Question 10

What is often associated with depressions?

Answer 10

Strong winds and heavy rain

Question 11

What way are depressions blown in the northern hemisphere?

Answer 11

Anti-clockwise

Question 12

How can a cold front be identified?

Answer 12

Bold lines with triangles

Question 13

What does a cold front indicate?

Answer 13

A change in air mass where warmer air is being replaced by colder air

Question 14

What are the characteristics of a cold front?

Answer 14

Often bring short spells of heavy rainfall in the form of showers and winds
Accompanied by a decrease in temperature
Veer in wind direction

Question 15

How can warm front be identified?

Answer 15

Bold lines with semi-circles/ humps

Question 16

What does a warm front indicate?

Answer 16

Cold air being replaced to a warmer air mass

Question 17

What are the characteristics of a warm front?

Answer 17

Often bring prolonged sometimes heavy rainfall with strong winds

Question 18

What happened in July 2007 in the UK?

Answer 18

A major flood event

Question 19

What were the irregular weather conditions in 2007?

Answer 19

Jet stream followed an abnormal southern direction

Question 20

What is the role of the jet stream?

Answer 20

Important for control factor for low pressure weather systems in the northern Atlantic

Question 21

What did a change in the jet stream mean?

Answer 21

Usual anticyclonic/ high pressure weather system from Azores failed

Question 22

What is the Azores?

Answer 22

Region of Portugal

Question 23

What happened in the uk due to the shift of the jet stream?

Answer 23

Resulting weather patterns produced exceptional rainfall throughout England and Wales

Question 24

What were the resultant conditions in the UK during 2007?

Answer 24

Mean temperatures across the UK were generally 1*c warmer
June precipitation was 136mm 190% average form 1961-1990 (wettest June on record)
Rainfall for may to July 2007 highest on record

Question 25

Why were the soils in 2007 highly saturated?

Answer 25

Early summer rainfall in 2007 meant that soils were already close to saturation and groundwater levels were higher than usual

Question 26

What are ground water levels like in a normal year in the UK?

Answer 26

Britains usually has lower ground water levels reducing the risk of flooding (acts as extra storage)

Question 27

When did some intense storms occur during summer 2007?

Answer 27

20th of July

Question 28

What did the intense storm on the 20th July result in?

Answer 28

A number of localised but severe flash floods

Question 29

What were some areas that experienced flash floods of 20th July 2007?

Answer 29

Stratford upon Avon Leamington spa Tewkesbury Buckingham

Question 30

What were the economic effects of the 2007 summer flood?

Answer 30

Cost country £3.2bn £2bn for homeowners and businesses

Question 31

What was the average repair cost of a flooded home in 2007?

Answer 31

£23,000- £30,000

Question 32

What was the problem for homeowners after the 2007 flood?

Answer 32

1/4 of homeowners were not fully covered by insurance

Question 33

What was the average cost per flooded business after the 2007 flood?

Answer 33

£75,000 - £112,000

Question 34

How much did the damage to communications and transport cost?

Answer 34

£230m

Question 35

What was the agricultural loss after the 2007 flood?

Answer 35

Loss of £50m £1,150 per hectare

Question 36

What was the cost to the emergency services during/after the 2007 flood?

Answer 36

£27m

Question 37

What were the social impacts of the 2007 Uk flood?

Answer 37

Education- 400,000 pupil days lost due to school closures Flooding of water treatment plant in Tewkesbury (worst post WW2 emergency) loss of piped water to 350,000 customers, 138,000 properties for over 2 weeks

Question 38

What were the demographic impacts of the 2007 UK flood?

Answer 38

13 people were killed Rural households worse affected- stranded as minor roads not considered as important as major roads in towns and cities Old and young most affected as they’re least mobile

Question 39

When did storm Desmond occur?

Answer 39

2015-16

Question 40

What were the meteorological causes of storm Desmond?

Answer 40

Unusually heavy rain and strong winds due to low pressure from the Atlantic

Question 41

How much rain did Honister in Cumbria get in 24 hours?

Answer 41

341.4mm

Question 42

How high did winds get in storm Desmond?

Answer 42

81mph

Question 43

How many categories are there for depressions?

Answer 43

5 categories

Question 44

What are the wind speeds for each depression category?

Answer 44

1- 74-95mph 2- 96-110mph 3- 111-129mph 4- 130-156mph 5- 157+mph

Question 45

How does a tropical depression form?

Answer 45

When low pressure is with thunderstorms that produce circular wind flow with maximum sustained wind flow below 39mph

Question 46

What is the typical maximum sustained wind speed for tropical depressions?

Answer 46

25-35mph

Question 47

When was the flood in Bangladesh?

Answer 47

1998

Question 48

What were some of the causes of flooding in Bangladesh?

Answer 48

Monsoon climate Spring snowmelt Deforestation in headwater area River silt-up Lying on a floodplain Diversion for irrigation Regularly hit by cyclones

Question 49

How did a monsoon climate cause flooding in Bangladesh?

Answer 49

Brings very heavy rain and snow Soils are leached and heavy runoff results in soil erosion

Question 50

How does spring snowmelt cause flooding in Bangladesh?

Answer 50

Results in soil erosion and a rapid increase in river discharge

Question 51

How does deforestation in headwater area cause flooding in Bangladesh?

Answer 51

Trees are cleared for fuel and grazing land for growing population Less evapotranspiration More runoff Faster soil erosion

Question 52

How does river silt up cause flooding in Bangladesh?

Answer 52

Raises river bed and reduces capacity of the channel

Question 53

What % of Bangladesh is built on a floodplain?

Answer 53

80% most of which is only 1m above sea level

Question 54

How does irrigation cause flooding in Bangladesh?

Answer 54

Removes som of the silt and prevent s the floodplain further downstream from being built up