thunderstorms and severe weather

  1. What are the characteristics of a thunderstorm?
    • cumulonimbus cloud with lightning and thunder
    • often heavy rain and gusty winds
    • some have hail or tornadoes
    • average cell - 15 mi in diameter lasting 30 min
    • multicell clusters are most common
  2. What characterizes a severe thunderstorm?
    • wind > 58 mph
    • hail > 3/4 inch
    • generates a tornado
  3. What conditions cause a severe thunderstorm?
    • daily heating
    • squall line from a front
    • dryline
    • sea breeze convergence
    • outflow boundary
  4. What are the hazards associated with thunderstorms?
    • hail
    • wind
    • lightning
    • tornadoes
    • flooding
  5. How much lightning is cloud to cloud?
    80%
  6. How hot can lightning be?
    54,000 degrees F (air)
  7. How many get killed in the US every year by lightning/injured?
    • kills 100 per year
    • injures 300 per year
  8. How does lightning form?
    • large electrical charge imbalance
    • upper cloud has + charge
    • lower cloud has - charge
    • charge is induced below thunderstorm on ground
    • stepped leader of ionized air branches downward
    • spark jumps from tall object to stepped leader
    • flowing electrons create return stroke
  9. What do you do and what do you avoid when caught outside in a thunderstorm with lightning?
    • avoid contact with metal
    • take cover if at an outdoor event
    • don't be the tallest point around
    • don't huddle with other people, spread out
  10. How are buildings protected from lightning strikes?
    lightning rods thanks to Ben Franklin
  11. How can lightning kill you indoors?
    • on a corded, landline telephone
    • typing on a desktop computer
    • taking a shower or bath
    • near an open window, opening, or on the porch
  12. How is risk from thunderstorms mitigated?
    • forecasting:  doppler radar
    • predicting:  watches and warnings
    • construction:  windproofing, community shelters
    • personal actions:  NOAA radio, prepared safe room
  13. What are other hazards from weather and their risks?
    • blizzards: extremely low visibility, wind chill effect and frostbite
    • fog: extremely low visibility, smog and vog even worse
    • ice storms: ice accumulates destroying utility lines and trees, travel not possible
    • drought: crops fail, food shortages
    • dust storms: widespread roof and tree damage, contribute to wildfires
    • heat waves: heat stress, dehydration
  14. How do humans exacerbate these weather hazards?
    • flooding
    • urban heat island
    • global warming
  15. Mesoscale Convective System (MCS)
    large, circular, long-lived and interacting group of thunderstorms
  16. linear belts
    • squall line
    • a line of thunderstorms
  17. mammatus clouds
    cellular pattern of pouches hanging underneath the base of a cloud
  18. stepped leader
    a channel of ionized air that approaches the earth in a series of nearly invisible bursts
  19. fulgerite
    natural hollow glass tubes formed in sand or soil when lightning strikes
  20. superbolt
    • positively charged
    • originates from top of cloud
    • 3 to 100 times more powerful than regular lightning
  21. lightning crouch
    last resort way of crouching if you are in lightning prone area
  22. 30:30 rule
    • take shelter when flash to bang is less than 30 seconds
    • remain in safe place for 30 min after hearing last thunder
  23. National Weather Service
    a branch of NOAA that is responsible for weather forecast and preparation of weather maps
Author
robynchristine
ID
270593
Card Set
thunderstorms and severe weather
Description
GEOL 1301 Review Topics for Exam III
Updated