L5 - Extreme weather in the UK

• the uk is a meeting point of different types of weather from different directions
• polar air mass from arctic sea brings cold, showery weather
• arctic maritime air mass comes from arctic and brings snow in winter
• polar continental air mass comes from central europe and brings dry summers and cold air brings snow in winter
• tropical continental air mass comes from africa and brings hot weather in summer
• tropical maritime air mass comes from atlantic and brings rain and mild weather
• the uk has a temperate climate
• the uk has cool summers and mild winters
• the uk has a smaller annual temperature range than continental climates
• the high and low pressure systems bring day to day changes to the UKs weather
• low pressure systems are called depressions
• high pressure systems are known as anticyclones
• extremes of low pressure in the uk bring storms, strong winds and heavy snowfall and blizzards
• extremes of high pressure bring long periods of drought or bitterly ice cold conditions in winter
• the winters of 1946-47 were exeptionally cold and take over if depressions are not passing over the uk as usual
• weather risk of cold weather in uk include:

  • frost - crops and cattle may not survive extremes
  • freezing conditions that can affect transport
  • blizzard conditions that causes transport to come to a halt
• flooding is caused by heavy rainfall or strong waves brought by a depression
• flooding may cause landslides as a secondary hazard
• coastal flooding is caused by:

  • depressions bring storm surges
  • strong winds funnel coastal water into the mouth of a river
• river flash flooding is caused by:

  • high intense rainfall
• slow onset river flooding is caused by:

  • steady rainfall that saturates the soil
• surface water flooding is caused by:

  • intense rainfall collects in hollows and depressions
• the UK is regularly hit by depressions which bring very heavy rainfall and trigger river floods
• drought can also happen in england and can be defined as an extended period of low or absent rainfall relative to the expected average for a region
• the longest drought occurred over an 18 month period
• reducing risk of drought:

  • a hosepipe ban for affected regions
  • water supplies turned off in houses
  • encourage houses to have a water meter fitted
• reducing risk of flood:

  • the thames barrier to protect london
  • monitoring of ground moisture levels
  • higher insurance on flood plains
• reducing risk of storms:

  • Met office improvement of prediction
  • Severe weather warnings on phones
  • Cancelled transport to minimise risk
• reducing risk of cold weather:

  • clearing roads of snow and ice
  • announcements in the media for warnings
  • raise public awareness of old people
• researchers say heat waves that previously occurred once every three years are now happening every 200 days thanks to global warming
• in the south east of england, temperatures used to reach 33 degrees once every 1000 days but now are happening once every 200 days
• extreme heatwaves and heavy rain storms are happening with increased regularity
• the ten hottest years on record have all come within the last 20 years, 6 of the 10 wettest years on record have come in the last 20 years