Extreme weather takes the lives of 14 people


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Tornados ripped through eastern Texas on Saturday night. (Red Cross/flickr)
Jenna Ladd | May 2, 2017

Flooding and tornados swept across the Midwest and southern U.S. this weekend, leaving at least 14 people dead.

The National Weather Service reported that four tornados moved through eastern Texas beginning Saturday evening. The twisters left an area of destruction 35 miles long and 15 miles wide in Van Zandt County, according to Canton, Texas Mayor Lou Ann Everett. Primarily small towns were affected in the mostly rural area east of Dallas; four individuals lost their lives.

Strong winds and flooding in Arkansas took the lives of five residents near Madison county. Four additional deaths were reported in Missouri and Mississippi, also due to flash flooding and strong winds.

Tragically, severe weather events like these are becoming more common as climate change rears its ugly head. According to archived data from the U.S. Environmental Protection Agency’s webpage prior to President Trump’s inauguration, “In recent years, a larger percentage of precipitation has come in the form of intense single-day events.” Similarly, the amount of precipitation falling on the heaviest rain days has increased in the last few decades. Many regions of the U.S. are seeing significantly more severe river flooding, while other areas are ravaged by drought. The Midwest, Great Plains, and Northeast have seen a significant increase in flooding, but the Southwest has experienced a decrease.

Scientists are still evaluating the relationship between climate change and twisters. The EPA notes that climate change does lead to stronger and more frequent thunderstorms, which can cause tornados, but there is a lack of empirical data on the matter.

Researchers can confidently conclude that climate change has caused more intense and frequent heat waves, fewer frequent and less intense cold waves, and regional changes in floods, droughts, and wildfires.

Winter tornados move through Midwest


West of Tuscaloosa, Alabama
(Frank/flickr)
Jenna Ladd | March 2, 2017

More than 20 tornados ripped through parts of Iowa, Missouri, Illinois, Indiana and Tennessee on Tuesday.

The severe thunderstorms and tornadoes killed at least three people and left thousands of residents in the Midwest and Southeastern U.S. without electricity. While tornados during winter months are rare, they seem to be happening with increasing frequency.

Typically wintertime tornados form when a forceful jet stream moves across the Southern U.S. and meets colder, retreating air fronts. According to The Weather Channel, usually these tornados crop up in the Deep South, however, in February 2016 severe tornados touched down in Pennsylvania and Virginia, ultimately killing seven people.

On average, February is second-least tornadic month of the year, but recently averages for that month are increasing. February 2008 had 146 total tornados, making it the most tornadic February since the 1950s, and February 2016 came close behind with 138 total twisters.

While an abundance of scientific evidence links climate change with the increasing frequency of extreme weather events like heat waves and coastal flooding, the relationship between climate change and tornado frequency remains unclear.

Due to particularly strong jet-stream level energy characteristic of the winter months, winter tornados can occur at any time of the day or night, unlike more predictable spring and summer tornados that almost always form during the late afternoon and evening. The Weather Channel also points out that it is common for winter twisters to be wrapped in rain, making them more difficult to spot.

Experts remind Midwestern and Southeastern U.S. residents that severe weather in the winter months can be deadly and to create or review their severe weather plans.

tornadoes-by-month
(The Weather Channel)

Researchers perplexed by tornado clusters’ growing size


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An image of a tornado touching down in Oklahoma in May of 1981 from the National Oceanic and Atmospheric Administration’s photo archive. (NOAA/flickr)
Jenna Ladd | December 2, 2016

A recent study in the journal Science reveals that tornado outbreaks are growing in size, and scientists are unsure why.

The study was published just days after 18 tornadoes devastated parts of the Southeast United States Tuesday night into Wednesday morning. The study’s lead author, Michael Tippett of Columbia University, said that 50 years ago tornado clusters, may have involved about 12 tornados, now they average roughly 20. The researchers studied the most extreme outbreaks, which happen about once every five years, and discovered a steady increase in tornado cluster size since the mid-1960’s.

Before the outbreak on Tuesday, 2016 had seen a record low number of tornadoes. In an interview with the Associated Press, Tippett said,“Something’s up. The tornadoes that do occur are occurring in clusters. It’s not any increase in the (total) number of tornadoes.” In contrast with upticks in other kinds of extreme weather, researchers are not seeing a connection between human-induced climate change and larger tornado clusters. Tippett said, “It’s not what we expected. Either it’s not climate change because not everything is, or it is some aspect of climate change we don’t understand yet.”

The article mentioned that the circulation of warm water in the Pacific and Atlantic oceans could be responsible for the tornado clusters’ growth over the years, but there is no evidence yet to support this claim.

Other scientists question the validity of Tippett’s study, claiming that increased reporting and the prevalence of urban sprawl may be responsible for the perceived growth of tornado outbreaks. One critic is Howard Bluestein, a meteorology professor at the University of Oklahoma. He said, “It’s a useful exercise, but I would be very, very careful in accepting it.”

Seven people were killed by this week’s tornado cluster, several more were injured.

On the Radio: Smoke linked to tornado intensity, UI study finds


Damage to the roof of St. Patrick Catholic Church in Iowa City from a 2006 tornado. (Laura Crossett / Flickr)
Damage to the roof of St. Patrick Catholic Church in Iowa City from a 2006 tornado. (Laura Crossett / Flickr)
April 13, 2015

This week’s On the Radio segment looks at a recent study by University of Iowa researchers who found a link between smoke from fires and tornado intensity. Listen to the audio below, or continue reading for the transcript.

**Please feel free to download the audio file for this On the Radio segment and distribute to friends, colleagues or media. To download the mp3 file, right click this link and choose “Save Link As…”

Transcript: Tornadoes

A recent University of Iowa study has found that smoke from fires can contribute to the intensity of tornadoes.

This is the Iowa Environmental Focus.

The study was published in the journal Geophysical Research Letters earlier this year. The researchers examined how smoke affected a system of severe weather events which occurred on April 27, 2011. This system produced 122 tornadoes and caused 313 deaths across the southeastern United States. The study found that smoke particles in the atmosphere lowered the base of the clouds and affected the speed of the winds which increased the intensity of the tornadoes. The research was conducted using computer simulations.

CGRER co-director Greg Carmichael and CGRER postdoctoral fellow Pablo Saide were co-authors of the study, along with researchers from other University of Iowa departments, the University of Wisconsin-Madison, and NASA.

For more information about tornadoes and for a link to the study visit IowaEnvironmentalFocus.org

From the UI Center for Global and Regional Environmental Research, I’m Jerry Schnoor.

http://now.uiowa.edu/2015/02/ui-researchers-link-smoke-fires-tornado-intensity

http://onlinelibrary.wiley.com/doi/10.1002/2014GL062826/abstract

Study: Tornado season striking ‘tornado alley’ earlier than in previous decades


Nick Fetty | September 18, 2014
An F1 tornado near Secor, Illinois in 2004. (Jim/Flickr)
An F1 tornado near Secor, Illinois in 2004. (Jim/Flickr)

A new study by the Department of Land Resources and Environmental Sciences at Montana State University found that peak tornado seasons are occurring about two weeks earlier in parts of ‘tornado alley’ compared to six decades ago.

The study examined tornado activity in Kansas, Nebraska, Oklahoma, and northern Texas from 1954 through 2009. Current peak tornado activity generally occurs from early May to early July. The study found that the peak of the tornado season in the 1950s occurred an average of seven days later in the year compared to now. When the data from Nebraska is removed the difference is nearly two weeks.

The researchers hope to use their findings to better prepare for future tornadoes, however, they are left scratching their heads as to what is causing this shift. Record keeping for tornadoes in the United States did not begin until the 1950s and because of this scientists are unable to study longer term trends of tornado activity.

The shift in the timing of the tornadoes can be attributed various factors such as the land’s topography as well as climate and it is difficult to pinpoint a single cause. Climate change  has also been named as a possible contributing factor, as meteorologist Greg Carbin points out: “If winters are not as cold, or if spring times are warmer, the location of the jet stream is most likely displaced north of where it has been in the past.”

Although not included in the study, portions of Iowa are often considered part of ‘tornado alley.’ A 2012 list compiled by weather.com ranked Iowa sixth in the nation based on tornadic activity. According to data from ToradoHistoryProject.com, there were approximately 2603 tornadoes resulting in 85 fatalities in Iowa between 1950 and 2013.

On the Radio: Big Ten professors link extreme weather to climate change


Photo by CR Artist, Flickr.

Listen to this week’s radio segment here or read the transcript below. This week’s episode links the extreme weather events of 2012 to climate change.

Climate experts from every  Big Ten universities signed a letter linking the extreme weather events this year to climate change.

This is the Iowa Environmental Focus.

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