Transcript Diverse Climate & Terrain in the West

LIVE INTERACTIVE LEARNING @ YOUR DESKTOP
NOAA: Storms and Drought: Climate
Change Impacts on the West
Presented by Eric Boldt
November 14, 2011
STORMS
DROUGHT
CLIMATE CHANGE IMPACTS ON THE WEST
My story
You were thinking this?
Poll Question
The diverse climate and terrain in the Western U.S.
results in annual rainfall of less than 5 inches in the
deserts to more than 200 inches per year in the
mountains.
√
X
True
or
False?
Diverse Climate & Terrain in the West
Wettest in the
mountains
Driest in the
deserts
Los Angeles County in Southern CA
Mountains 6000-10000 ft
LA
Coast-Valleys 0-1500 ft
Winter Storms
floods
Western Storm Impacts
Heavy
Precipitation
Strong Winds
Small
Tornadoes
and waterspouts
High Surf
and rip currents
Large Waves
December 21, 2010
Poll Question
“Atmospheric Rivers” are known as…
a. A little known rock band from the
Midwest
b. Rivers that flood when it rains
c. Plumes of tropical moisture in the
atmosphere
d. Jet streams
Atmospheric Rivers associated with heavy
precipitation events
Wetter
Amount of water vapor in the atmosphere to generate precipitation
December
17-22, 2010
Atmospheric River
brings 15-25 inches
of rain to southern
CA in 5 days.
ARkStorm is a USGS
led project to model
the impacts of a
catastrophic flood
event in California.
The term “Atmospheric
River” is used to explain the
moist conveyor belt
associated with Pacific
storms. Also known as the
“pineapple express.”
http://pubs.usgs.gov/of/2010/1312/
NASA/NOAA project to measure
Atmospheric Rivers
Aircraft drone
NASA’s Global Hawk launched from Edward’s AFB in February 2011
Flight path of NASA’s Global Hawk for a mission in February 2011
WISPAR – Winter Storms and Pacific Atmospheric Rivers
project measured water vapor content from approaching
storms during February 2011.
Poll Question
What severe weather phenomenon results in the
most annual fatalities in the U.S.?
a.
b.
c.
d.
Tornadoes
Lightning
Flash floods
Hurricanes
Heavy precipitation
days have increased
(measurable trend)
Increase in precipitation intensity
is consistent with the observed increases in atmospheric water vapor
Increase in the amount of daily precipitation
over North America that falls in heavy events
Precipitation intensity is a key
component of severe weather.
Flash floods, debris flows, and
snowfall intensity can be very
destructive and life-threatening.
Winter storm tracks are shifting
northward and the strongest
storms are likely to become
stronger and more frequent,
with greater wind speeds and
more extreme wave heights.
Source – www.globalchange.gov
More powerful
storms will
increase threats
to life…
…and property
Time For Questions
???
Drought
heat waves
wildfires
Poll Question
How important is mountain snowpack for water
supply in the Western U.S.?
a.
b.
c.
d.
Not that important
Somewhat important
Important
Very important
WOW!
Nearly 75% of the water
supply in the Western
U.S. comes from
mountain snowpack
65% in California – source Dept. Water Resources
Departure from normal snow depth for
February 27, 2011
Drought seriously depletes water resources
Lake Oroville, CA – Feb. 2008
Winter
Summer
Winter
January 2011
When the West
would normally
get precipitation
it was abnormally
dry.
Annual Precipitation - % Change
Drier
Drier
Heat waves impact health mainly due to.....
[place clip art on a box below]
High humidity
Warm nights
Existing health
issue
Heat Waves
•
•
•
•
warm overnight temperatures
prolonged temperatures 15-20 degrees above normal
combination heat and humidity makes it feel hotter
poor air quality and smoke compounds health impacts
Warm night temperatures will increase
Increase in the percentage of very warm nights over North America
...On average excessive heat
claims more lives each year
than floods, lightning,
tornadoes and hurricanes
combined...
Source – NWS
Temperature Change
Wildfires
Are fires
becoming
more
frequent?
Are they more severe?
Poll Question
What do you think? Are wildfires more severe
than in the past?
[place clip art on a box below]
Yes
No
Don’t
know
More acres burned per fire
National Interagency Fire Center – wildland fire statistics
More total acres burned annually
Other factors are involved like disease, forest age,
politics, causes, or is it climate change?
Time For Questions
???
Monsoon
flash floods
Most areas of Northwest
Mexico and the Southwest U.S.
receive over half their annual
precipitation from the monsoon
Source – NWS Tucson, AZ
Winter
Summer
Winter
Monsoon depends on
winds and heat to
transport moisture from
the Gulf of California
Monsoon
moisture
brings summer
thunderstorms
to much of the
Rockies. Flash
floods, and in
some cases,
wildfires, are
caused by
these storms.
Will climate change impact the monsoon?
...possibly
Average monsoon start dates
by decade
1950s July 1
1960s July 2
1970s July 2
1980s July 6 Latest on record (7/25/1987)
1990s July 3
2000s July 7 Earliest on record (6/17/2000)
Other Severe Weather
tornadoes
hurricanes
Poll Question
Do tornadoes occur in California?
a. Yes
b. No
c. Don’t know
Pt. Mugu, CA 2008
Sacramento, CA 2005
Long Beach, CA 2009
Riverside, CA 2008
In southern California – this 1200 sq. mile area has
the highest frequency of tornadoes west of the
Continental Divide
J. Hales study 1997-1998 El Niño (32 events in 21 days)
Tornado history across the
United States – since 1950
There is no clear trend in the
frequency or strength of tornadoes
since the 1950s for the United
States as a whole...
...however, the frequency of
favorable conditions for severe
thunderstorms is likely to increase.
Source – www.globalchange.gov
Poll Question
Have tropical cyclones occurred in California?
a. Yes
b. No
c. Don’t know
1858 Hurricane – San Diego
1939 Tropical Storm – Long Beach
3 other known tropical cyclones have
impacted the SW – California, Arizona
Hurricane Linda 1997
Tropical Cyclone Storm Tracks
As ocean temperatures
rise, the strongest
hurricanes are likely to
increase in both the
eastern Pacific and the
Atlantic.
Source – www.globalchange.gov
Time For Questions
???
Climate
observations
resources
More than 11,000 volunteers take observations on farms, in urban and suburban areas,
National Parks, seashores, and mountaintops.
COOP – Cooperative Observer Program
CoCoRaHS is a grassroots volunteer network of backyard weather
observers of all ages and backgrounds working together to measure and map
precipitation (rain, hail, and snow) in their local communities.
NOAA Global Monitoring Exhibit
NWS Los Angeles/Oxnard, CA
www.weather.gov
RECAP
 Winter storms bring many types of severe weather to the
West
 Drought severely impacts water resources
 Heat waves and wildfires may get worse
 The monsoon is critical for desert Southwest precip
 Tornadoes and hurricanes do occur in California
 Opportunities for climate observing and NWS resources
FOR LISTENING!
Thank you
Eric Boldt
Warning Coordination Meteorologist
National Weather Service Los Angeles/Oxnard
[email protected]
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