Heavy rainfall events more common nationwide


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This map illustrates the percent increase in heaviest precipitation events from 1958 through 2016. (Climate Central)

Jenna Ladd | May 11, 2018

As the climate continues to warm, many U.S. cities are experiencing heavy rainfall more frequently.

Research and news organization, Climate Central, examined the number of days per calendar year that each of 244 sites nationwide experienced 0.25, 0.50, 1, and 2 inches of precipitation from 1950 through 2017. The report found that incidents of heavy rain events are increasing in frequency in all regions of the U.S. In Des Moines, the number of days per year where the city experienced two or more inches of precipitation has increased by about seven percent since 1950.

For each 1°F of global warming, Earth’s atmosphere becomes four percent more saturated with water. This makes more moisture available to condense and fall down as precipitation. As a result, extreme floods are more likely to happen now than they were in the past. According to NOAA, 29 flood disasters that cost more than $1 billion each have happened since 1980. In Iowa alone, floods have caused more than $18 billion in damages in the last thirty years. That puts us in fourth place nationwide for the number of floods experienced since 1988.

The northeastern United States has seen a 55 percent increase in heavy precipitation events from 1958 through 2016, the sharpest increase in the nation, according to the report. The midwest follows close behind, with a 42 percent increase in heavy precipitation events.

Users can determine whether incidents of heavy rainfall have increased in Dubuque, Mason City, Ottumwa, Sioux City, and Waterloo by using Climate Central’s interactive map.

Iowa Flood Information System predicts economic damages of flooding


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The Mississippi River in Dubuque is one of many in the state that is threatening to flood this spring. (Lesley G/flickr)

Jenna Ladd | May 10, 2018

Flooding has cost Iowa communities more than $18 billion in the last thirty years, and as the Mississippi and Cedar Rivers continue to swell this spring, Iowans may wonder how much they can expect to pay out on flood disasters in the future.

In recent years, scholars at the Iowa Flood Center have been working to predict just that. HAZUS, developed by the the Federal Emergency Management Agency, provides predictions of the economic impact various magnitudes and types of natural disasters might have across the United States. During 2017, Research Engineer and Assistant Professor Ibrahim Demir and graduate research assistant Enes Yildirim, combined HAZUS’ information on demographics, buildings and structural content with data from the Iowa Flood Information System (IFIS).

As a result, IFIS now offers flood loss and economic damage estimations for twelve communities in the state. These include Cedar Rapids, Cedar Falls,  Des Moines, Fort Dodge, Iowa City, Independence, Kalona, Monticello, Ottumwa, Rock Rapids, Rock Valley, and Waterloo. HAZUS’ model makes it possible for users to not only view the overall economic damages to a community but also how much in damages individual buildings can be expected to accrue.

Iowa Flood Center researchers are working to expand this predictive model to other parts of the state. For now, users can use the following guide to learn more about the financial consequences of flooding in any of the aforementioned communities.

First, users must visit Iowa Flood Information System website, then:

  1. Hover their cursor over the “Flood Maps” tab and find their community under the “Flood Map Scenarios for Communities” button.
  2. After clicking on the “Damage Estimate” button, users can toggle the “Flood Map Controller” to model different scenarios.

Residents evacuated due to flooding in Western Montana


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The Clark Fork River runs through the center of Missoula, carrying water down from the mountains. (Frank Fujimoto/flickr)

Jenna Ladd | May 9, 2018

Sixty homes in Missoula, Montana were mandatorily evacuated due to flooding on Tuesday.

Heavy precipitation during early May and recent snowmelt from nearby mountains mixed to send rivers and streams in several parts of Western Montana flowing out of their banks. The Clark Fork River is a main artery running through the middle of Missoula and is the site of the most severe flooding. 1,300 homes along the river were encouraged to prepare for a possible evacuation.

Ken Parks is the Missoula County Disaster and Emergency Services deputy coordinator. He said to the Associated Press, “If you live anywhere near a stream or waterway in western Montana you need to be prepared to leave your home. This is going to come earlier than we expected. We’re trying to get out ahead of this thing and get the message out that this could be a very dangerous situation.”

From 1955 to 2016, snowpack on mountains in the Western United States declined by an average of 23 percent, according to the U.S. Environmental Protection Agency. However, Western Montana has really only seen the beginning of this spring’s snowmelt, according to authorities from the National Weather Service. Some parts of the local mountain range are expected produce 55 additional inches of snowmelt through the spring and summer. The Clark Fork River is expected to reach higher levels than it has since 1981 this year.

Extreme weather costlier than ever in 2017


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Jenna Ladd | March 28, 2018

As the Northern Hemisphere enters warmer seasons where severe weather and flooding are more likely, it is yet to be seen whether 2018 will top 2017 as the most costly year for natural disasters ever.

Since 1980, the yearly average for natural disasters in the U.S. that cause more than $1 billion in damages has been 5.8 events. Last year, the country saw 16 such events, including three tropical cyclones, eight severe storms, two inland floods, a crop freeze, drought and wildfire. While this number technically ties with 2011, 2017 had more extreme weather as wildfires are tallied by region rather than single events, and last year brought more wildfires costing upwards of $1 billion than ever before.

According to NOAA’s National Centers for Environmental Information, the total cost of severe weather last year was $306.2 billion. This surpassed the previous record by nearly $100 billion dollars. Hurricanes Harvey, Irma and Maria caused $265.0 billion of 2017’s damages. Researchers figure physical damages to buildings and infrastructure as well as crop damages and losses to business into the total cost.

The midwest U.S. saw at least two severe storms last year that caused more than $1 billion in damages, both of them in mid-June. Flooding associated with storms like these has caused some $13.5 billion in economic losses from 1988 to 2015 in Iowa alone, according to a recent op-ed by Iowa Flood Center Director Witold Krajewski. Midwesterners also faced early tornado outbreaks in 2017, which tore across the region in late February and early March. Both events cause more than $1 billion in damages.

The National Centers for Environmental Information point out that increased development in vulnerable areas like coastlines, floodplains and fire-prone areas are causing the increase in billion dollar disasters. Climate change plays a role too. They write,

“Climate change is also paying an increasing role in the increasing frequency of some types of extreme weather that lead to billion-dollar disasters. Most notably the rise in vulnerability to drought, lengthening wildfire seasons and the potential for extremely heavy rainfall and inland flooding events are most acutely related to the influence of climate change.”

2017 Iowa Water Year summary released


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The Iowa DNR recently released the 2017 Water Year summary. (Dirklaudio/flickr)
Jenna Ladd | October 10, 2017

The 2017 Water Year came to an end recently according to a report from the Iowa Department of Natural Resources (DNR).

The “water year” runs from September 30th through October 1st. Overall, the 2017 water year has been drier and a bit warmer than usual. The statewide precipitation average was about 32 inches, which is roughly 3.28 inches less than usual. Precipitation was around average during the winter months, but fell below normal during the summertime.

Temperatures in the state averaged 50.7 degrees Fahrenheit, which made 2017 the fourth warmest year on the Iowa DNR’s 144 year record. While temperatures were mostly typical during the growing season, they were higher than usual for most of the winter months. This year brought the second warmest November and the third warmest February on record.

The complete 2017 Water Year summary can be viewed here.

An economic argument for slowing climate change


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Damages from Hurricane Harvey are estimated to exceed $100 billion. (Jill Carlson/flickr)
Jenna Ladd | September 29, 2017

Human-induced climate change costs more than the U.S. economy can afford according to a recent report from the Universal Ecological Fund.

The Economic Case for Climate Action in the United States,” published recently by the non-profit research organization, found that severe weather intensified by climate change and the health impacts associated with burning fossil fuels have cost the U.S. economy $240 billion per year in the last decade.

Economic losses due to extreme weather have doubled in the last ten years. To illustrate this point, the authors point out that Hurricanes Harvey, Irma and Maria caused an estimated $300 billion in damages, which is double the $145 billion in losses caused by all hurricanes in the last decade.

The press release points out that the number of extreme weather events costing $1 billion or more in damages has increased by 400 percent since the 1980s. Iowa, for example, has endured three floods costing more than $1 billion in the last decade, up three fold since the 1990s.

If climate change is not curtailed, researchers predict annual costs associated with severe weather and the health impacts of greenhouse gases will reach $360 billion.

Sir Robert Watson, coauthor of the report and former Chair of the Intergovernmental Panel on Climate Change said during a press conference, “Simply, the more fossil fuels we burn, the faster the climate continues to change and cost. Thus, transitioning to a low-carbon economy is essential for economic growth and is cheaper than the gigantic costs of inaction.”

Lessons for Iowans in the wake of Harvey


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A map from the National Hurricane Center illustrates predicted landfall for Hurricane Irma, a category 5 storm, over the weekend. (National Hurricane Center)
Jenna Ladd| September 7, 2017

As some of the floodwater finally recedes from the Houston area following Hurricane Harvey,  Hurricane Irma, a category five storm, threatens to devastate the Florida Keys this weekend.

Climate change increased the amount of rainfall that fell on Houston during the recent storm, according to a statement from Clare Nullis Kapp, media officer for the World Meteorological Organization. Karen Tigges, a Des Moines resident and operations analyst at Wells Fargo, said in a recent Des Moines Register Letter to the Editor that Harvey has something to teach the people of Iowa. The letter reads:

“Houston: A tragic example of a city caught at the mercy of worsening storms and increased rainfall. Flooding is nothing new to Houston, but it appears that this time they are really paying the price for unwise growth.

Unfortunately, flooding is not unfamiliar to the city of Des Moines either. We are growing in the metro as well. We must take the warnings of storm events seriously. It’s said that the lack of zoning ordinances in Houston led to the loss of wetlands and grasslands that could have absorbed at least some of the onslaught of water. How does that compare with planning for growth here in the metro area? Is the growth of our urban areas leading to higher risks of flooding due to more impermeable surfaces in the form of more paved roads and rooftops?

As the city prepares for a future that will likely include more intense rainfall events, thanks to a warmer, more humid climate, we citizens need to take an active role in seeing that effective planning and policies are put in place to make Des Moines ready to face this unpleasant reality.

We can do that by weighing in on the city’s new planning and zoning code. We also need to do that by electing and supporting leaders that will be proactive in setting the course of the metro area on a path of resilience and preparedness for what storms of the future may bring.”

— Karen Tigges, Des Moines