Record Breaking Precipitation and Floods in Iowa

The Winter and Spring of 2019 set several records in the Quad Cities, which is located in eastern Iowa. In January of 2019, the Quad Cities saw 28.8” of snowfall, beating the previous record of 26.7” in January of 1979. On Thursday, May 2, 2019 the Mississippi River broke a record set back in 1993 for reaching the highest level ever recorded at 22.7 feet. Also in the Spring of 2019, the Mississippi River in the Quad Cities was above flood stage (18 ft.) for 96 days in a row, crushing the previous record of 42 days set back in 1993. According to the Bettendorf Mayor Bob Gallagher, the reason for the flooding was due to the fact that between May 2018 - May 2019 the state of Iowa received more precipitation than had previously been recorded in the past 124 years of data. At the same time, the global average temperature has increased by 2 degrees Fahrenheit, and more water vapor can be held in a warmer atmosphere. Furthermore, since 1979 the amount of Arctic Sea ice at Earth’s North Pole has decreased by 3.3 million square kilometers and it continues to decrease by 13% every decade. NASA predicts that as more ice turns to water and more water vapor is held in a warmer atmosphere, the midwest can expect to see more flooding in the future.

• How could a melting ice sheet in the North Pole mean more precipitation in Iowa?

• Why did the Quad Cities experience record-breaking precipitation and flooding in the Spring of 2019? 
• Why does NASA suggest that all communities in the Midwest should brace for an increase in flooding events in the future?

Students could:

• Review information, videos, and data showing record-breaking floods that have occurred in their area recently. 
• Brainstorm why they think this flooding has occurred, and most importantly, why NASA suggests that more flooding is expected to occur in the Midwest in the future. (Note: Teachers should make sure that the students don’t have easy access to resources when the students are brainstorming their answers to these questions, and students should be challenged to come up with questions that will help them figure out if their ideas are correct or not.)
• After allowing students to generate ideas and questions, teachers should guide students through a model that shows how an increasing global temperature increases Arctic Sea ice melt and the amount of water vapor held in the atmosphere, thus more precipitation/flooding will occur. (The increase in water vapor and decrease in sea ice act as a positive feedback loop which increases global temperatures further because water vapor is a greenhouse gas and less sea ice means less (albedo) sunlight reflected into outer space and away from the Earth.)

• NPR | The Mississippi River Has Been Flooding for 41 Days Now: This website contains an article from NPR documenting the devastating flooding that occurred in the Quad Cities in the Spring of 2019.
• NASA | Climate Change & Global Warming: This website from NASA contains data on Arctic Sea ice melt, increasing carbon dioxide levels and global average temperature, as well as effects that this will have on different parts of the country.
• NASA | The Study of Earth as an Integrated System: Information on planet feedbacks related to climate change can be found on this website.