On The Radio – September 2017 record-setting month for hurricanes

Hurricane Maria churning over the Atlantic Ocean. (NASA)
Jenna Ladd | October 23, 2017

This week’s On The Radio segment discusses the unprecedented severity of hurricane activity in the Atlantic ocean this September. 

Transcript: September 2017 was a record-setting month for hurricane activity in the Atlantic Ocean.

This is the Iowa Environmental Focus.

It is common for September to be the most active month for hurricanes because low pressure systems often move across the Atlantic and meet the tropical waters of the Caribbean during that month, but September 2017 was a cut above the rest.

The beginning of September brought Hurricane Harvey, a category four storm which caused unprecedented damage to, Houston, the U.S.’s fourth largest city. Five additional hurricanes left paths of destruction across the Caribbean and Florida during September, with Irma and Maria both reaching category five status.

Last month, the overall intensity and duration of storms, known as “accumulated cyclone energy,” was 175 units, significantly higher than September 2014’s record of 155 units. While climate change has not been found to cause hurricanes, there is evidence to say that rising sea temperatures make them stronger.

For more information, visit Iowa-environmental-focus-dot-org. From the UI Center for Global and Regional Environmental Research, I’m Betsy Stone.

Researchers perplexed by tornado clusters’ growing size

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.

Wet conditions hamper fieldwork in May

Fall crops and standing water from rains in 2009 in Polk County (Carl Wycoff / Flickr)
Fall crops and standing water from rains in 2009 in Polk County (Carl Wycoff / Flickr)
KC McGinnis | June 2, 2015

Rain, cool temperatures and standing water halted Iowa farmers for parts of last month, slowing crop progress by limiting suitable days in the field.

The USDA’s National Agricultural Statistics Service reports that in the last week of May just 2.3 days were suitable for fieldwork across the state, with only 1.7 suitable days for southwest Iowa. Topsoil moisture was rated at above surplus for 50% of southwest and south central Iowa, and 22% across the state. That’s compared to last year, when only 7% of Iowa topsoil was at surplus moisture.

This excess moisture has made it difficult for farmers to get in their fields, leading to lags in soybean planting and alfalfa hay first cutting, which was only at about half the five-year average. Some operators reported standing water in their fields, and some fields will need to be replanted due to the excess water. The moisture also prevented spraying, and led to concerns over muddy feedlots.

While 92% of soybeans were planted by the end of May last year, this year’s numbers were at 50% or less for parts of the state, with southwest Iowa reaching only 37%.

Iowa faced a similar situation last year, with consistent heavy rains in June and July leading to less than three suitable field days for three consecutive weeks. “We just came through three of our most challenging years, as far as weather goes,” noted northeast Iowa farmer Travis Holthaus in a recent CGRER documentary. Heavy rains, flash flooding and challenging droughts continue to lead to increased unpredictability for Iowa farmers. These producers may need to prepare for decreased field days in the next week as well, with more storms predicted later this week.