Climate

Must-Read on 2011’s Unprecedented Rains and Wet-Dry Extremes, Just What You’d Expect From Global Warming

Remarkably, more than half of the country (58%) experienced either a top-ten driest or top-ten wettest year, a new record.


Percentage of the contiguous U.S. either in severe or greater drought (top 10% dryness) or extremely wet (top 10% wetness) during 2011, as computed using NOAA’s Climate Extremes Index. Image credit: NOAA/NCDC.

by Jeff Masters, cross-posted from the WunderBlog.

Rains unprecedented in 117 years of record keeping set new yearly precipitation totals in seven states during 2011, NOAA’s National Climatic Data Center revealed in its preliminary year-end report for 2011.

Precipitation rankings for U.S. states in 2011. Seven states had their wettest year on record, and an additional ten states had a top-ten wettest year. Texas had its driest year on record, and four other states had a top-ten driest year. Image credit: NOAA’s National Climatic Data Center.

An extraordinary twenty major U.S. cities had their wettest year on record during 2011. This smashes the previous record of ten cities with a wettest year, set in 1996, according to a comprehensive data base of 303 U.S. cities that have 90% of the U.S. population, maintained by Wunderground’s weather historian Christopher C. Burt. Despite the remarkable number of new wettest year records set, precipitation averaged across the contiguous U.S. during 2011 was near-average, ranking as the 45th driest year in the 117-year record. This occurred because of unprecedented dry conditions across much of the South, where Texas had its driest year on record.



Wettest, driest, and warmest year records set during 2011 for major U.S. cities. No major cities had their coldest year on record during 2011. Image credit: NOAA’s National Climatic Data Center.

2011 sets a new U.S. record for combined wet and dry extremes [see top graph]
If you weren’t washing away in a flood during 2011, you were probably baking in a drought. The fraction of the contiguous U.S. covered by extremely wet conditions (top 10% historically) was 33% during 2011, ranking as the 2nd highest such coverage in the past 100 years. At the same time, extremely dry conditions (top 10% historically) covered 25% of the nation, ranking 6th highest in the past 100 years. The combined fraction of the country experiencing either severe drought or extremely wet conditions was 58%–the highest in a century of record keeping. Climate change science predicts that if the Earth continues to warm as expected, wet areas will tend to get wetter, and dry areas will tend to get drier–so 2011’s side-by-side extremes of very wet and very dry conditions should grow increasingly common in the coming decades.

23rd warmest year on record, and 2nd hottest summer for the U.S.
The year 2011 ranked as the 23rd warmest in U.S. history, with sixteen states recording a top-ten warmest year on record. Delaware had its warmest year on record, and Texas its second warmest. However, these statistics don’t convey the extremity of the summer of 2011–the hottest U.S. summer in 75 years. The only hotter summer–and by only 0.1°–was the Dust Bowl summer of 1936, when poor farming practices had turned much of the Midwest into a parking lot for generating extreme heat. The June – August 2011 average temperatures in Texas and Oklahoma were a remarkable 1.6°F and 1.3°F warmer than the previous hottest summer for a U.S. state–the summer of 1934 in Oklahoma. The U.S. Climate Extremes Index (CEI), which is sensitive to climate extremes in temperature, rainfall, dry streaks, and drought, indicated that an area nearly four times the average value was affected by extreme climate conditions during summer 2011. This is the third largest summer value of record, and came on the heels a spring season that was the most extreme on record. When averaged over the entire year, 2011 ranked as the 8th most extreme in U.S. history, since the fall weather was near-average for extremes. The CEI goes back to 1910.


Average temperatures for the summer in Texas and Oklahoma, at 86.8 degrees F (30.4 degrees C) and 86.5 degrees F (30.3 degrees C), respectively, exceeded the previous seasonal statewide average temperature record for any state during any season. The previous warmest summer statewide average temperature was in Oklahoma, during 1934, at 85.2 degrees F (29.6 degrees C). Image credit: National Climatic Data Center.

Wunderground’s weather historian Christopher C. Burt has a more detailed look at the U.S. extremes observed during 2011 in his latest post. His selection for the most remarkable yearly record set during 2011:

Perhaps, most astonishing is the total annual rainfall of just 1.06” at Pecos, Texas (normal annual precipitation is 11.61”). If confirmed this would be a Texas state record for least amount of precipitation ever recorded in a calendar year, the current record stands at 1.64” at Presidio in 1956.

— Jeff Masters is co-founder of the Weather Underground. This piece was originally published Masters’ WunderBlog.

For background on the science of extreme weather with links, see these Climate Progress posts:

one of the opening statements, which I’m sure you’ve probably heard is “Well you can’t attribute a single event to climate change.” But there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. And the prospects are that these kinds of things will only get bigger and worse in the future.

8 Responses to Must-Read on 2011’s Unprecedented Rains and Wet-Dry Extremes, Just What You’d Expect From Global Warming

  1. prokaryotes says:

    Look it is a baby Hockey Stick!!

  2. Solar Jim says:

    At first glance, I wasn’t sure whether to feel a sense of retribution toward drought ridden Texas oil country from global warming or a sense of sadness. As an American, the latter wins hands down.

    It is difficult to go through withdrawal when everyone around is addicted (to the “wealth”) and the political economy is orchestrated by globalized petro-corporatists. Reminds me of the economic history of slavery. Yet, this time the response will not be of humans but of natural law. And natural laws (like physics) have no mercy.

  3. Spike says:

    Just started re-reading Mark Lynas’ book on climate Six Degrees. Interestingly the first bit of the one degree chapter speculates on the US SW states facing mega-drought as happened around 1000AD for around 300 years with the modest warming of the Mediaeval Warm Period.

    One gets the feeling we are going to live through times of consequence.

  4. Lionel A says:

    Meanwhile, in the UK there are already signs of spring (mentioned also in Huff Post) which portends trouble from ecological disruption between inter-dependant forms of life. Between plants and insects and working up the web of life to birds and mammals – which latter includes us of course.

    Here is a reminder of the long history of denier perfidy .

  5. Dennis Shibut says:

    Here in France the climate is showing the same extremes for 2011. Meteo France has officially declared 2011 as the warmest year on record (since 1900) for France. The rise in average temperatures throughout the country was 1.5C; the previous record was 1.3C set in 2003.

    The rainfall showed similar extremes as in the U.S. The whole of the southwest(!) of France was parched with only 40 percent of its normal rainfall, and other areas especially to the east near the Alps were flooded with 500 percent rainfall.

    I have also read Lynas’ book “Six Degrees” and in the same chapter concerning the first one degree of warming, he mentions the computer models (circa 2006) predicting the drying out of southern Europe as global warming progresses. That is what is happening here in the south of France and in the north as well. Despite the extreme floods in specific areas this spring and summer, the average rainfall for France dropped 17 percent below normal.

  6. John McCormick says:

    Expansion of the subtropical zone, both north and south, is measured and monitored. Just a matter of time before Southern Europe desertifies.

    Read up on tropical expansion and Hadley cells.

  7. Mike Straub says:

    Time to start promoting innovations that will lead us away from fossil fuels, and not just the old standbys. (wind/solar/etc…) They’re helping, but it’s going to take more. Take a look at Ocean Thermal Energy Conversion, creating endless emission free power from the temperature difference in warm shallow water, and cold deep water. It’s been proven for decades, and is about to go commercial in the Caribbean. Plus, the only byproduct of an OTEC system is clean drinking water. Seriously life-changing stuff. The Bahamas is building 2 OTEC plants, and other countries are working in their own deals.

    Here’s more info on the Bahamas projects, and other OTEC benefits….
    http://www.theonproject.org/2011/the-bahamas-sign-memorandum-of-understanding-to-build-two-otec-plants/?utm_source=thinkprogress&utm_medium=web&utm_campaign=mscomment