This document discusses El Niño and La Niña weather phenomena in the Pacific Ocean and their impact on weather patterns. El Niño occurs when warm water builds up off the coast of South America due to weak trade winds, while La Niña happens when strong trade winds cause colder than normal water temperatures. These shifts in ocean temperature can significantly affect weather worldwide, such as causing floods in some areas and droughts in others. The document provides definitions of El Niño and La Niña, their causes, typical duration and examples of damage caused by each.

1. El Nino and La Nina

2. What weather
phenomena has the
largest impact on
weather in the
western US ?

4. Definitions:
La Niña - Unusually cold surface water
temperatures in the Pacific ocean caused
by strong easterly trade winds.

6. El Niño - Unusually warm surface water
temperatures in the Pacific ocean caused
by weak (or reversed direction) easterly
trade winds.

8. El Niño and La Niña
simplified…
El Nino is the
abnormal heating of
Earth’s ocean surface
in the Pacific.
La Nina is the
abnormal cooling of
Earth’s ocean surface
in the Pacific.

9. Did You Know…
El Nino means “The
Christ Child”
They were discovered
hundreds of years
ago
They can be caused
by underwater
volcanoes
La Nina means “Little
Girl”
They occur half as
often as El Nino’s

10. Time Pattern
El Nino usually lasts
from a year to two
years.
The longest El Nino
ever recorded lasted
six years.
La Nina usually lasts
nine to twelve
months.
The longest ever
recorded lasted three
years.
El Nino La Nina. Oracle Think Quest. Retrieved May 14th, 2012. http://library.thinkquest.org/5818/elnino.html

11. Causes:
El Nino is caused
when trade winds
allow warm water
from the Pacific to
flow east.
This builds up warm
surface water that will
soon cause the El
Nino.
La Nina is caused
when the
temperatures drop in
the pacific, also being
blown east.
This builds up at the
coasts and will cause
a La Nina.

12. What causes an El Niño?
Weak trade
winds and
weak
upwelling
cause warm
water off the
coast of S.
America

13. What causes a La Niña?
Strong trade
winds blow
surface water
towards east,
creating colder
surface
temperatures off
South American
coast. We get
strong
upwelling.

14. What causes the patterns?
Normal

15. Movement of Ocean Water
Surface currents
Deep ocean currents
Upwelling

16. Surface Ocean Currents
Currents that are controlled by
the wind. ~¼ mile depth, 10%

17. Deep Ocean Currents
Currents controlled by water
density: temperature and salinity
90% of the
ocean water
moves in deep
ocean currents

18. Upwelling
upwelling brings up cold, nutrient-rich
waters to the surface, which encourage
seaweed growth and support blooms of
phytoplankton.

19. Upwelling
 This happens along the coast, and when this happens it
creates animal diversity.
 Phytoplankton use these nutrients to grow and
reproduce at rapid rates.
 This attracts organisms to areas of upwelling that rely
on phytoplankton as food and, in turn, attracts their
consumers.
 This areas is rich in biological activity and diversity.
 Approximately half of the fish caught in the world come
from areas of upwelling.

20. El Nino’s Damage Done
 Floods in the Pacific
states
 Cause tornadoes in the
mid-west states
 Causes severe
thunderstorms in the
south
 Northeast typically has
stormy winters,
"Snowmageddon”

21. La Nina’s Damage Done
 Drier and Milder
conditions in the south.
 Cause severe droughts in
the southeast.
 Cause unusual cold
temperature changes
along the Pacific coast.
 Causes wetter conditions
for the Pacific states.
 Northeast will have cold
periods

22. Strange phenomenon
occur during an El Niño and
La Niña like...

23. Brush fires caused by drought in
Texas (La Niña)

24. Increased Tropical Storms (La Niña)

25. Hurricane Floyd was HUGE!
(1999 - La Niña)

26. Causing devastating floods in
Australia (2010-2011 La Niña)

27. Peruvian anchovy populations
declined (El Niño)

28. Star Tribune Aug 2 1993
Minneapolis, MN
FLOODS
Upper
Mississippi
Basin
Source: Trenberth

29. NO!!!
Scientists have found no significant correlation between El
Niño and La Niña weather patterns and increased tornadoes.
More tornadoes through tornado alley?

30. The drought of 1988: cost about $40 billion

32. Watch Videos (3 minutes each)
 Science Cheat Sheet
http://science.discovery.com/tv-shows/cheat-
sheet/videos/el-nino-and-la-nina.htm
 National Geographic Video
http://video.nationalgeographic.com/video/environment
/environment-natural-disasters/landslides-and-more/el-
nino
 La Nina water movement explained
 https://www.youtube.com/watch?v=8qJYCHBEj2g

33. A
B
C
QUIZ! Which is which…
Normal, El Niño, La Niña?

34. Were you’re predictions correct?

35. Videos : If time
 http://www.youtube.com/watch?v=SR5VPAqVQBw El Nino explanation
video 3min

 http://www.youtube.com/watch?v=jEAv-9TZktY La Nina explanation
video 3.5min

 http://www.youtube.com/watch?v=iWTucpsClLc Austin newscast in
January talking about Australia flooding 2min

 http://www.youtube.com/watch?v=l5x8dJ57xkk Texas weatherman
predictions for this year from July 2010. about 3min

 http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNin
a.html All three animations