For decades, Illinoisans have been vulnerable to the effects of climate change, which are expected to worsen in the future. Rising temperatures in all seasons lead to more severe heat waves, extended drought, air quality issues, and extreme storms. With historical changes in the intensity and frequency of rainfall, flooding occurs more often, potentially leading to public health hazards, such as water contamination and exposure to infectious diseases.

Illinois State Climatologist Trent Ford is the state’s authoritative spokesperson on climate science. Ford has been in this position since 2019, but the role was initiated by state statute in the 1950s at the Illinois State Water Survey (ISWS). Ford talks frankly about climate change to raise awareness and encourage action.

Ford speaks with a wide variety of groups in communities and at conferences, drawing on data he has gleaned from University of Illinois research, meteorologists, and federal agencies. He is also the point person with climate science expertise, offering climate projections to state government agencies and participating in developing documents such as the state water plan and the state hazard mitigation plan. He also brings specific climate change issues to the forefront.

One example is the need for legislation for a group vulnerable to the ever-increasing extreme heat: migrant farm workers.

“I’ve been harping about migrant farm workers for over two years now,” Ford said. “There are only four states in the US that have any legislative protection for them in experiencing extreme heat, and Illinois is not one of them. This group is completely unprotected.”

During this past summer’s drought, Ford took responsibility to stay on top of the conditions for the duration to understand the drought’s complexity and ensure that weather and drought monitoring were sufficient to capture data. From April to August when the drought lessened somewhat, Ford spoke to as many as 70 reporters about drought conditions in Illinois.

This year has also been especially challenging for Ford because of tornadoes, dust storms, air quality problems from wildfires, and heat waves.

“I’m having to triage,” he said. “This is really a clear sign of changes in the climate system, the fact that we are having years like this when there are way more extreme events than we can possibly dig into.”

Ford has co-authored several research articles, including “Effects of 0.5°C less global warming on climate extremes in the contiguous United States“. More information about climate change is on the Illinois State Climatologist website.

As Illinois experiences record-breaking rainfall stretching from Chicago to Cairo, ISWS researchers collect data and update climate models for Bulletin 75, the publication that provides Illinois’ standards for expected extreme storms.

“The heavy precipitation in Illinois and the Midwest presents a significant challenge in terms of stormwater management,” hydrologist Momcilo Markus said. “To address the problem effectively, more accurate predictions of future rainfall intensity and frequency are critical and require up-to-date assessments of current climate conditions and model-generated data for future horizons.”

Markus, a co-author of Bulletin 75, uses climate modeling projections, which indicate that not only is rainfall expected to increase, but that the amount of the increase will grow.

Effective January 2020, the Illinois Department of Natural Resources Office of Water Resources and District 1 of the Illinois Department of Transportation began requiring Bulletin 75 rainfall for newly initiated projects. The Federal Emergency Management Agency (FEMA) will also accept Bulletin 75 rainfall data for projects and map revisions. Illinois counties and communities are expected to update ordinances that will adopt the new Bulletin 75 standards for building structures based according to a predefined storm magnitude and duration.

Bulletin 75, supported by the Illinois Department of Commerce and Economic Opportunity and the US Department of Housing and Urban Development, used an additional 34 years of data from an earlier version, revealing that the number of storms in Illinois producing over 2 inches of rain has nearly doubled over the past century. During that span, the statewide average annual precipitation has increased 11% and temperatures have risen by 1.2 degrees.

“Climate modeling projections indicate that not only have we seen an increase in rainfall, but that this will increase in the future,” said Markus, “The 100-year, 24-hour rainfall is about 1 inch higher than the old one in the Chicago area — this is 13% higher.”

A 24-hour, 100-year storm event is the amount of rain that should accumulate in a 24-hour period for a storm with a 1-in-100 (or 1%) chance of occurring in a given year. Earlier versions of Bulletin 75 state that a 24-hour, 100-year storm event will result in approximately 7.58 inches of precipitation. 

The new data suggest Illinoisans should expect nearly an additional inch of rainfall for a 24-hour, 100-year storm event, or 8.57 inches instead of 7.58 inches. 

Flooding is predictable in certain areas, yet too many Illinoisans suffer economic and personal losses when flooding occurs. Homeowners insurance does not cover flood damage, although floods are the most common natural disaster in Illinois, accounting for well over 90% of declared disasters. Financial losses are not reserved to big disasters — just 1 inch of water can cause $25,000 of damage to a home.

To help reduce further losses, the Coordinated Hazard and Assessment Program (CHAMP) engineers, geographic information system (GIS) specialists, and outreach staff conduct studies and work with communities to accurately identify high-risk areas where flooding from rivers and streams is likely to occur.

In the early 2000s, CHAMP was initiated at the ISWS with four staff members to modernize paper Flood Insurance Rate Maps (FIRMs) by converting them into countywide digital products (dFIRMs) as part of FEMA’s Flood Map Modernization effort. FEMA later transitioned the effort into the Risk Mapping Assessment and Planning program, a broader, ongoing program that encompasses a wider range of activities, including risk assessment (flood studies), community engagement, and flood risk mitigation planning.

The CHAMP team, now with about 30 staff members, conducts flood studies using hydrologic and hydraulic modeling of surface water from precipitation events to understand flood risks across the state, as federal funding through FEMA allows. Flood mapping updates are an ongoing process since climate and land use changes can affect rivers and streams. CHAMP has conducted studies on thousands of stream miles in Illinois involving every major watershed in the state and has coordinated efforts with Illinois’ bordering states.

Portion of Champaign County’s Flood Insurance Rate Map (FIRM)

Working with county stakeholders has long been a part of map revisions, but staff have built even closer ties with government and county officials in newer efforts to assist with hazard mitigation plans that encompass earthquakes, tornadoes, heatwaves, and other natural risks besides floods. In partnership with local officials, state agencies, and the U. of I. Extension, the team assembles information from various sources into county-specific plans that enable communities to be prepared for natural disasters and to be eligible for federal assistance when disasters are declared.

A FEMA-approved hazard mitigation plan must be updated every five years and is required for communities to receive federal funding when natural disasters are declared. CHAMP also participates with communities in procuring grants that pay for the development of the plans.

“We are able to collaborate with communities beyond just giving them a document,” Heistand said. “We are actively assisting them to the point of helping them with cost-sharing and grant management.”

CHAMP also acts as a liaison between local officials and the state and federal government as a Cooperating Technical Partner with FEMA. CHAMP is positioned to create and disseminate hazard-related information based on their knowledge of water resources in counties and ongoing relationships with county stakeholders.

CHAMP’s study results, modeling, data collection, and expertise hold value for other kinds of projects as well. For example, CHAMP recently completed a multi-phase project with the Metropolitan Water Reclamation District of Greater Chicago to study the effects of proposed changes to stormwater detention release rates on downstream flooding and water quality. CHAMP’s modeling repository is also useful for consulting engineers in designing land development projects. The models and data could find new uses in machine learning and artificial intelligence applications.

“Someday residents might ask an AI like ChatGPT, ‘What is the flood risk to my home?’” Heistand said. “The answer won’t be possible without all the work we’re doing now.”  

Information about county mitigation efforts and maps, projects, and studies is available at illinoisfloodmaps.org.