Weather and Climate Weather is becoming more extreme Evidence Evidence Events e.g. Boscastle 2004 and summer 2003 heatwave Events e.g. Boscastle 2004 and summer 2003 heatwave Impacts Impacts

What is extreme weather? 1 minute to list as many as you can 1 minute to list as many as you can

Extremely heavy rainfall Extremely heavy rainfall Blizzard Blizzard Drought Drought Heatwave Heatwave Tropical Storm Tropical Storm

What is extreme weather? Boscastle floods in August 2004 when 200mm of rain fell in 24 hours. The average for the whole August is 75mm.

The Boscastle flood, 16 th August 2004 The Boscastle flood, 16 th August 2004 Boscastle is situated on the North Cornwall coast. For a hundred years the village was a thriving port but the coming of the railways soon saw its decline as a trading port. About 90% of Boscastle’s economy is now reliant on tourism. On Monday 16 th August 2004 major flooding occurred in North Cornwall. The small village of Boscastle was devastated.

What were the causes of the Boscastle Flood? Climatic conditions were the main reason for the floods in Boscastle. 200mm fell over Ottersham Moor, to the east of Boscastle, within a 4 hour period. This was combined with coastal winds and a rising tide. The ground was also already saturated from previous rainfall events.

Skills Question – Using the image below, describe the damage (4 marks)

European Heatwave 2003 A blanket of deep red across southern and eastern France shows where temperatures were 10 degrees Celsius hotter in summer 2003 than in the other years. White areas show where temperatures were similar, and blue shows where temperatures were cooler in 2003 than in 2000,2001,2002 and 2004.

Morpeth Summer floods 2008 Summer 2008 was very wet summer causing flooding events in Somerset, Worcestershire, Morpeth and Northumberland. Q1. Write a definition of extreme weather using page 62 Q2. Make a bullet point list of the extreme events over the last ten years

What is the impact of extreme weather? People and their lives People and their lives Homes Homes Economy Economy Transport Transport Q3. Create a mind map or bullet point list under each heading to explain the multiplier effects of extreme weather events such as the Boscastle flood. Q4. What can be done to plan and prepare for extreme events like Boscastle?

Positive effects? Boscastle? Boscastle? Heatwave? Heatwave?

Responding to Extreme Weather We can’t stop the weather, but given the perceived increase in frequency of extreme events, the Met office has taken a 3 stepped approach to deal with it…. We can’t stop the weather, but given the perceived increase in frequency of extreme events, the Met office has taken a 3 stepped approach to deal with it….

Step 1 – Weather Advisory

Step 2 – Weather Warning When it is felt that there is over 60% confidence in the prediction, this more serious warning is given (usually closer to the time) When it is felt that there is over 60% confidence in the prediction, this more serious warning is given (usually closer to the time)

Step 3 – Flash Warning Over 80% confidence that the weather will hit (usually just a few hours notice) Over 80% confidence that the weather will hit (usually just a few hours notice)

The Environment Agency Offer help, advice and can evacuate areas Offer help, advice and can evacuate areas May make changes such as building flood defences if the problem is deemed likely to return May make changes such as building flood defences if the problem is deemed likely to return

Frequency Is based on historical records of how often that level of flood occurs. Is based on historical records of how often that level of flood occurs. Boscastle = 1 in 400 year flood Boscastle = 1 in 400 year flood To protect against such a rare event would be seen as not cost effective To protect against such a rare event would be seen as not cost effective However, if events are becoming more frequent, who is to say that the 1 in 400 years may not now be a 1 in 10 year event? However, if events are becoming more frequent, who is to say that the 1 in 400 years may not now be a 1 in 10 year event?

Cost-Benefit Analysis 1 in 400 year event 1 in 400 year event Cost to repair damage + lost income =£50m Cost to repair damage + lost income =£50m Cost to build flood defences to withstand that level of flood = £5m Cost to build flood defences to withstand that level of flood = £5m Cost over the next 10 years Defences No Defences Cost over the next 10 years Defences No Defences Cost over the next 50 years Defences No Defences Cost over the next 50 years Defences No Defences Cost over the next 100 years Defences No Defences Cost over the next 100 years Defences No Defences

In the end, they settled for a smaller defence system costing £800,000 In the end, they settled for a smaller defence system costing £800,000 Was it worth it? Was it worth it? Boscastle 2007 Boscastle 2007 Boscastle 2007 Boscastle 2007

Are they really getting more frequent? Heatwaves UK – 1906, 1911, 1921, 1933, 1934, , 1983, 1989, 1995, 2006 Heatwaves UK – 1906, 1911, 1921, 1933, 1934, , 1983, 1989, 1995, 2006

Are they really getting more frequent? Extreme Rainfall UK – 1893, 1901, 1952, 1953, 1960, 1967, 1975, 1989, 2004, 2007, 2011 Extreme Rainfall UK – 1893, 1901, 1952, 1953, 1960, 1967, 1975, 1989, 2004, 2007, 2011 And what about Lynmouth? (Look familiar Boscastle?) And what about Lynmouth? (Look familiar Boscastle?)