Extreme Weather and Climate Change in IowaNow and Future Trends

Christopher J. Anderson, PhDAssistant Director, Climate Science Program

Iowa State University

Adapting to Weather Extremes: The Economic Impact in IowaDes Moines, Iowa

11 December 2013

Losses From Damaging Weather2000-2004

Average Number2008-2012

Average Number2000-2004Total Loss

(2009$ Millions)

2008-2012Total Loss

(2009$ Millions)

Tornado1 3.8 5.2 10.50 137.76

Hail1 354 324.4 unavailable unavailable

Wind1 400.8 557.8 unavailable unavailable

Flood2 unavailable unavailable 1,472.427* 2,974.663

Corn Yield3,4 141.38 bu ac-1

148.12 bu ac-1

269.200 2,207.446

Soybean Yield3,4

43.4 bu ac-1 48.6 bu ac-1 391.568 608.138

*1999-2003 used for flood loss.1NWS Storm Data2NWS flood loss database

3USDA NASS4USDA RMA

Iowa EF2-EF5 Tornado Reports for 1953-2012

Data Source: NWS Storm Data

2008 - 2012

Tornado Reports during 1964-1968 and 2008-2012

1964 - 1968

Data Source: NWS Storm Prediction Center, http://www.spc.noaa.gov/climo/online/sp3/plot.php

Very wet years (red bars) are more frequent

• Average return of 1-in-12-year prior to 1980 and 1-in-3-year since 1980.• Red bars show >22% increase in rain and >55% in streamflow.Data Source: State Climatologist for Iowa

Very wet days (red bars) are more frequent

Data Source: State Climatologist for Iowa

Data Source: Stoner et al. (2012)

Frequency in very wet spring (red bars) is predicted to increase.

Ocean Provides Moisture for Rainfall:Warmer Ocean Means More Rainfall

Data Source: Brubaker et al. (2001)

What is causing more heavy rainfall events?

More water vapor is in the air over the Midwest.• Warmer water in Gulf of Mexico and Caribbean Sea• Wet soils more rainfall wet soils

Current Pacific Ocean temperature pattern reduces drought frequency.

• Storm systems move over rather than north of Midwest• Likely to continue for 10-20 years

Forward-looking climate data in Community Planning:Ames Flood Mitigation StudyFrequency of Years > 150% precipitation(a) 1953-2009 Data: 1 in 27(b) 1980-2009 Data: 1 in 21(c) Extrapolate 1980-2009Trend: 1 in 9

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Forward-looking climate data in vulnerability analysis:Iowa DOT Federal Highways Study

Climate predictionsfeed into hydrology model

U. Iowa hydrology modelgenerates streamflow

Iowa DOT evaluates vulnerability to streamflow.

Cutting edge climate science:Emergence of 10-yr Climate Predictions

A first-ever 10-yr forecast research project has been completed. It will be evaluated for the next 5 years.

Data Source: Meehl et al. (2013)

2016-2020 Initial Result:5-yr average temperatureis predicted to be less thanin previous predictions.

Damaging weather in IowaIncrease frequency of wet years and wet days is likely to

continue for the next decade.

Change in frequency or severity of tornadoes, wind, hail, and drought is not expected for the next decade.

Because the likelihood of one extreme has increased, the exposure to compound extremes has increased.

Sustained dialogue is critical for incorporating latest advances in climate science into community planning, policy, and regulations.