7. Five minutes after this picture was taken and the young woman had left,
The spot where she had been standing was struck by lightning.
One person was killed, one permanently disabled, and six others injured.
Source : Danielson, Levin & Abrams, Meteorology Second Edition, McGraw-Hill
Photo from NOAA
8. Lightning & Aviation
All Nippon Airways Boeing 747 being struck by lightning
while taking off from Osaka, Japan
13. The
30/30
seconds minutes
Rule
If you hear thunder after
Seeing lightning less than 30 seconds,
Seek shelter!
Wait at least 30 minutes
after the thunderstorm has passed
31. Case Study
Lightning striking a tree next to a home
in Park Township destroyed electrical
equipment and appliances in the home
and caused minor injuries to a child who
suffered mouth burns from her braces.
(USA)
35. Lightning Safety
If you’re outdoor
• Move to a sturdy enclosed building
• Get inside a hardtop vehicle.
• Do not stay under a large tree!
36. If you’re inside a car…
• Keep the windows rolled up
• Avoid touching metal parts
37. If you’re indoor…
• Unplug unnecessary
electrical appliances
• Turn off air conditioners
and computers (to protect them
from power surges)
• Do not use a corded phone
(except in an emergency)
48. ภาพดัดแปลงจากสไลด์ของ ดร.คมสัน เพ็ช
Propagation:
t
striking distance
Lightning progress in step, each 10 - 200 m, average ~
50 m.
Speed of downward step is 1 m/µs = 1,000,000 m/s (approx.).
The last leg is very important, as objects will create a streamer.
The one met with the leader first, it will be struck.
53. กรณีอ ื่น ๆ ที่ค ล้า ยคลึง กัน
• Lightning struck close to a garage where
a 23-year old man was working on a metal
table. The man felt a numbness
and was taken
to the hospital. (USA)
54. Case Study
• A lightning strike traveled along phone lines
and ruined several pieces of equipment. (USA)
All forms of lightning connect oppositely charged regions inside clouds or on the ground. Four types of lightning in the above picture are In-cloud Lightning Inter-cloud Lightning Negative Lightning Positive Lightning
Bolt from the Blue Positive lightning flashes across clear sky, form the positively charged top of thunderclouds to the ground several kilometers from the storm.
The 30/30 Rule: Step 1: When you see lightning, count the seconds until you hear thunder. Step 2: If this time is 30 seconds or less, quickly go inside a substantial building. If such a building is not available, a metal-topped vehicle is the next best choice. Step 3: Wait at least 30 minutes after seeing the last lightning or hearing the last thunder before going back outside. Note : Sound speed at 25 C is 346 m/sec, so in 30 seconds sound can travel 10.5 km. This means that you are in danger of being struck by a positive flash. * เสียงเร็ว = 346 m/sec ที่ 25 องศาเซลเซียส ดังนั้น 30 วินาที => 10.5 กิโลเมตร
Recommended Lightning Safety Information NOAA National Severe Storms Laboratory Lightning Safety – What you need to know NOW! http://www.nssl.noaa.gov/edu/safety/lightning.html
