Deadliest weather disaster of 2011: the East African drought
The deadliest storm of 2011 is Tropical Storm Washi, which is now being blamed for 957 deaths in the Philippines. Washi's heavy rains triggered devastating flash flooding on the island of Mindanao last Friday. However, the deadliest weather disaster of 2011 is a quiet one that has gotten few headlines--the East African drought in Somalia, Kenya, and Ethiopia. On July 20, the United Nations officially declared famine in two regions of southern Somalia, the first time a famine has been declared by the UN in nearly thirty years. Almost 30,000 children under the age of five were believed to have died of malnutrition in Somalia this summer, and the total death toll of this great drought is doubtless much higher. At least thirteen million people in East Africa are in need of food aid. However, conditions are improving. Food aid has lifted three of six provinces in Somalia out of famine. The "short rains" of the October - November rainy season were plentiful this year--too much so, since heavy rains killed 15 people in Kenya and left 80,000 homeless in early December. The flooding was worsened by the preceding drought, which killed much of the vegetation that ordinarily would have stabilized the soil and absorbed rainwater before it could run off and create destructive floods. The rains have allowed a good harvest to be planted this fall, and with continued food aid, the Somalia famine should ease by spring 2012. ReliefWeb reports that in the three Somalian provinces still experiencing famine, nearly 250,000 people face imminent starvation, though.
Figure 1. The impacts of the Horn of Africa drought on cattle in Somalia in 2006. Image credit: USGS
Meteorology of the East Africa drought
East Africa has two rainy seasons--a main "long rains" of March - June, and the "short rains" of October - November. The "short rains" failed in 2010, due to a sea surface temperature pattern featuring cooler than average waters in the western Indian Ocean, and warmer than average waters in the Eastern Indian Ocean (a negative "Indian Ocean Dipole.") When the main "long rains" in spring 2011 also failed, it brought one of the worst droughts in recorded history. The 2010 - 2011 drought was rated along with the droughts of 1983 - 1984 and 1999 - 2000 as one of the three most significant droughts of the past 60 years. It was the driest 12-month period on record at some locations in East Africa.
Figure 2. The "long rains" of March - May 2011 failed over much of East Africa, leading to drought and famine (left image.) However, the "short rains" of October - December have been up to five times higher than normal, easing the East Africa drought. Image credit: NOAA Climate Prediction Center.
The uncertain future of drought in East Africa
The climate of East Africa during the main March - June rainy season has steadily dried over the past 30 years. Since 2004, six of the past eight years have seen unusually deficient spring "long rains." This drying of the East African climate has come as the waters of the Indian Ocean have warmed significantly. A 2011 study by A. Park Williams and Chris Funk of the University of California, Santa Barbara, blames the drought in East Africa on the heating up of the Indian Ocean, which has altered the atmospheric circulation over East Africa to bring more sinking air and less moisture. The atmospheric circulation over East Africa is part of Earth's largest atmospheric circulation feature--the Walker circulation. The Walker circulation features rising air over the warmest waters of the Pacific Ocean, and compensating sinking air over over eastern tropical Africa and the eastern tropical Pacific. The Walker circulation also helps drive the El Niño/La Niña phenomena in the Eastern Pacific. Williams and Funk show that the increase in Indian Ocean temperatures in recent decades has made the Walker circulation extend farther west, resulting in more sinking air over East Africa and thus less rain. Since the increase in Indian Ocean temperature driving this change in the atmospheric circulation shows strong linkages with human-caused global warming, they conclude: "anthropogenic [human-caused] warming appears to have already significantly altered the Earth's largest circulation feature and impacted its most food insecure inhabitants." They predict that East Africa will continue to dry as global warming increases the ocean temperatures in the Indian Ocean, impacting the Walker circulation. However, eighteen of the 21 models used in the 2007 IPCC report on climate change predict more rainfall over East Africa by the end of this century. These models predict that the Walker circulation will weaken, shifting towards a more "El Niño-like" state, resulting in less sinking air (and thus more rain) over East Africa. Since there is as yet no evidence of this happening, and East African climate has gotten drier in recent years, this may be a case where the large majority of the climate models are wrong. While the models used to formulate the 2007 IPCC report do a reasonable job simulating the the current climate over most of the world, they do a poor job of simulating Africa's current climate. The models put too much precipitation in southern Africa, and displace the band of heavy thunderstorms called the Intertropical Convergence Zone (ITCZ) too far south. The 2007 IPCC report concludes, "the absence of realistic variability in the Sahel in most 20th-century simulations casts some doubt on the reliability of models". In other words, since these models do a poor job simulating the current climate of the Sahel region of Africa, we shouldn't trust their predictions for the future climate of Africa.
Figure 3. Farmers in the Horn of Africa tend their emerging crops. Image credit: USGS.
Donations sought for the East Africa famine
Weather Underground has partnered with the International Rescue Committee (IRC) to help the Horn of Africa region during the ongoing famine. With the help of the Weather Underground community, we hope to raise $10,000 that will go toward helping the refugees survive the crisis. Weather Underground will match the community's donation dollar-for-dollar up to $10,000 for a total donation of $20,000. Please visit the East Africa famine donation page to help out. Ninety cents of every dollar donated goes directly to the people in need.
References
Behera, Swadhin K., Jing-Jia Luo, Sebastien Masson, Pascale Delecluse, Silvio Gualdi, Antonio Navarra, Toshio Yamagata, 2005: Paramount Impact of the Indian Ocean Dipole on the East African Short Rains: A CGCM Study. J. Climate, 18, 4514-4530. doi: http://dx.doi.org/10.1175/JCLI3541.1
Dai A., K.E. Trenberth, and T. Qian, 2004: A global data set of Palmer Drought Severity Index for 1870-2002: Relationship with soil moisture and effects of surface warming", J. Hydrometeorol., 5, 11171130.
Sheffield, J., K. M. Andreadis, E. F. Wood, and D. P. Lettenmaier, 2009, "Global and continental drought in the second half of the 20th century: severity-area-duration analysis and temporal variability of large-scale events", J. Climate 22, pp 1962-1981.
Williams, A.P., and C. Funk, 2011, A westward extension of the warm pool leads to a westward extension of the Walker circulation, drying eastern Africa, Clim Dyn (2011) 37:2417-2435 DOI 10.1007/s00382-010-0984-y
Other posts looking back at the remarkable weather events of 2011
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster
Wunderground releases its free iPhone and Android apps
Wunderground is proud to announce that our free Weather Underground iPhone app is now live in the iTunes store. The free Android version was released on Android Market last night. I've been having a lot of fun with the new apps; they're a great way to get weather info on the go.
I'll have a new post on Thursday.
Jeff Masters
Reader Comments
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I'd add another group: people who spent years--or even decades--up north of the snow line, and have vowed to never again let that chill soak into their bones. I've lived in Montana, Minnesota, Wyoming, Colorado, and Ohio (among others), so I'll be perfectly happy never seeing snow again.
We don't usually get this type of afternoon shower in the winter... more likely to see overnight showers with diurnal cooling to the dewpoint...
LOL
is interesting on a personal level, but I think this
is going to be more newsworthy over the next 24 - 48...
[Showing only the tail end over the GOM, btw]
Shup ST2K! Lol. ;-)
Yeah I do get what your saying. By the way, do to the absence of hurricanes over the last several years, the amount of people moving to Florida has gone way back up. I hate that, because I'm not trying to be critical, but most people who move here are far from environmentally friendly. In fact it seems many people that move to Florida ignorantly joke about their wastefulness. Sadly they "I don't give a crap" is the common attitude of many people that come here. I am certainly not saying that's always the case by any means. It just seems we Florida attracts a lot of people that aren't good for the state, and/or people you don't want as your neighbor either, LOL.
Like I said, that's not always the case of course, I can't label millions of people, I'm just saying it seems to be an unfortunate pattern.
How much rain did you receive? I see must areas got around 1.50".
Will check later this afternoon, was raining when I left for work, looks to be around 1.5 to 2 inches
Well I did say generally speaking, I have met people here who moved away from the cold and never, ever want to go back. I just know that the majority of people Ive met are long term Floridians like my family that once lived in cold and are glad to live in Florida, but we often get sick of continuous warmth that can go through the winter some years. I myself would never want to live in the north where its bitterly cold. But I wish a nice frequent chill, (highs in the 50's and 60's) would be more common and more reliable. I don't want endless cloudy days and 20's and 30's for highs every day and sometimes much colder than that, like you get in Michigan where my family came from. Ive been there when its very cold, windy, and constantly cloudy, it was interesting, but its certainly not something I'd want to live in lol.
I'm still happy to live here. Plus here in Tampa Bay our winters our consistently quite a bit cooler than yours our in Naples :) especially in terms of high temps and consistency. This is one of the warmest Decembers living here though. The last 2 winters were how I wish it always was here in the winter.
Posted on December 22, 2011
December 22, 2011 - TANZANIA - At least four people were killed in flash floods that hit many parts of Dar es Salaam Tuesday, with the Tanzania Meteorological Agency (TMA) issuing an alert over more heavy rains in coastal areas. The Dar es Salaam Regional Commissioner (RC), Mr. Said Mecky Sadick, confirmed the four deaths after chairing an impromptu regional Peace and Security Council meeting. Widespread destruction of property and infrastructure was evident in some streets and thousands of people were left homeless when their houses were swept away. TMA said the rains were caused by the building of pressure over the Indian Ocean, which created heavy clouds along the coastline. The situation might persist for at least two days. The downpour started at around 3am (East Africa time) with thunder and strong winds and led to a power blackout in many parts of the city. The downpour started at around 3am (East Africa time) with thunder and strong winds and led to a power blackout in many parts of the city. Traffic jams were common Tuesday morning, with many roads either flooded or partly damaged. The RC said at least four people were confirmed dead, including an infant whose body was found at Kwa Mtogole at Tandale. He named the other three as Ms Dhati Mseti, who was struck by lightning, Mr. Mgasa Saidi and Mr Abraham Lusama. Some witnesses reported seeing dead bodies floating in some streams. –Africa Review
Indeed, when I discussed it on here at first I was just getting started, I'm about 51 credits in now, I completed calculus 2 this fall, a very intense course so its nice to have that mile stone behind me lol. I'm ready for the spring term! The next big class of the Spring semester I'm taking will be Calculus 3, it looks more interesting than 2 though, because it has a lot more physics and real science application.
NATIONAL WEATHER SERVICE BIRMINGHAM AL
125 PM CST THU DEC 22 2011
ALC007-021-117-221945-
/O.CON.KBMX.TO.W.0171.000000T0000Z-111222T1945Z/
BIBB AL-CHILTON AL-SHELBY AL-
125 PM CST THU DEC 22 2011
...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHERN SHELBY...NORTH
CENTRAL CHILTON AND EAST CENTRAL BIBB COUNTIES UNTIL 145 PM CST...
AT 122 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR WILTON...OR NEAR MONTEVALLO...MOVING NORTHEAST
AT 45 MPH.
LOCATIONS IMPACTED INCLUDE...
CALERA...COLUMBIANA...AMERICAN VILLAGE...SHELBY COUNTY AIRPORT...
SAGINAW...CAMP BRANCH AND SHELBY.
THIS INCLUDES...
INTERSTATE 65 EXIT NUMBERS 228 THROUGH 238...
TO REPORT SEVERE WEATHER...CALL 1-800-856-0758.
LAT...LON 3293 8688 3298 8696 3308 8698 3334 8670
3315 8651
TIME...MOT...LOC 1925Z 230DEG 38KT 3309 8681
$$
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