Spring 2011 may well go down in the weather history books as the most extreme on record. From the massive April tornado swarm, to record Mississippi river levels, to extreme drought and wildfires in the Southwest, weather extremes were both violent and relentless, taking a terrible toll on human life and the economy.

Percent area of the contiguous U.S. experiencing much above average one-day precipitation events in spring 2011 was a record 16%. The 102-year average is 9%. (NOAA National Climatic Data Cente)

Consider all of the following additional examples of extraordinary weather and extraordinary weather records that occurred between March and May:

Historic tornado numbers and deaths:

* Most active April on record with 875 tornadoes (average number past decade: 161)
* Preliminary: Most January-May tornadoes on record (since 1950)
* 314 deaths from April 27 tornado outbreak, fourth most on record in a single day
* 151 deaths from Joplin, Mo. tornado on May 22, seventh most deaths from a single tornado on record
* Through June 7, 525 tornado deaths - sixth most on record in a single year (with six months still remaining, although Storm Prediction Center’s Harold Brooks said most tornadodeaths have historically occurred by mid-June)
* See also: Tornado swarm 2011: Overwhelming areal coverage

Extreme rainfall:

Spring average precipitation by state across the U.S. (March-May) (NOAA National Climatic Data Center)

* Wettest March-May on record in 10 states: Washington, Wyoming, Indiana, Ohio, Kentucky, West Virginia, Pennsylvania, New York, Vermont
* Wettest March-May on record in the Pacific Northwest region
* 300% of normal precipitation in the Ohio Valley
* 1300 daily precipitation records broken in April across Midwest and South; 72 locations reported their wettest dayin any April, five of which set all-time daily rain records (for any month)


* Record-setting crests along the Mississippi: Caruthersville (Mo.), Birds Point (Mo.), Vicksburg (Ms.), Natchez (Ms.), Red River Landing (La.); historic levels in many other locations including Memphis
* 6.8 million acres flooded in Lower Mississippi River Valley
* 3.5 million acres of farmland flooded within Lower Mississippi River Valley, including one million acres of farmland flooded in Arkansas and 900,000 acres of farmland flooded in Mississippi (10 percent of farmland in state)

Long-term measured size of Gulf of Mexico hypoxic (or dead) zone with 2011 forecast. Dark gray represents the range of ensemble forecast. (NOAA)

Extreme Drought and Wildfires

* Driest March-May on record in Texas
* Extreme to exceptional drought from southeast Arizona through New Mexico, much of Texas, and along the Gulf Coastline to the Florida panhandle.
* Driest March-May on record in Rio Grande Valley
* 26-day dry spell in many locations in Texas and New Mexico in April
* El Paso ended a record streak of 110 days without precipitation on May 24
* Most wildfire activity on record in April in U.S. (since 200), with almost 1.8 million acres burned
* From November 2010 to May 2011, Texas ranchers lost $1.2 billion because pastures have not greened; livestock losses are expected to exceed $1 billion due to lack of water and feed for cattle

Current U.S. drought monitor showing extensive drought conditions from the Southwest across the Gulf Coastline (U.S. Drought Monitor)

Billion dollar weather disasters (summary):

Billion dollar weather disasters in 2011 (NOAA National Climatic Data Center)


The onslaught of extreme weather events this past spring may have no equal in the historic record.. Harold Brooks, researcher at NOAA’s Storm Prediction Center, speaking at a press briefing Wednesday, said the most similar year to 2011 might be 1927 which had significant tornado activity and flooding. However, historic indicators of drought do not suggest similarly dry conditions in the Southwest that year.