Weekend storms were rare, but they reflect the new rainfall extremes in Wisconsin
While this storm may have been rare, intense rainfall events already have grown more common in Wisconsin and elsewhere.
The reason has nothing to do with politics and everything to do with science. Human activities, like burning fossil fuels, are changing the climate.
As our planet heats up, warmer air can hold more water vapor. For every one degree Fahrenheit of warming, the air can hold an extra 4% of moisture, according to the nonprofit climate science organization Climate Central.
That means when weather conditions are right for a rainstorm, there's more moisture to let go.
Emerging evidence also shows that a warmer climate produces slower-moving weather systems, said Wisconsin state climatologist Steve Vavrus. Winds in the upper atmosphere travel at slower speeds because of warmer arctic air, letting storms linger and dump more rain.
In this case, the storm hovered over the Milwaukee area for hours Saturday night and Sunday morning before finally moving on.
And while heavy rain doesn't always produce a flood risk, it's more likely in urban areas with concrete surfaces that can't soak up water, said Kristina Dahl, vice president for science at Climate Central.
On average, Wisconsin has become nearly 20% wetter since 1950, Vavrus said. That trend is more pronounced in the southern half of the state, including Milwaukee.
More: Milwaukee area flooding: Flooding resources, FEMA aid, closures from severe weather in southeast Wisconsin
More: Flood debris pickups, drop-offs and more resources for Milwaukee County and suburbs
More: How to clean up a flooded basement and prevent mold after Milwaukee floods
None of this is unique to Wisconsin.
According to the Fifth National Climate Assessment published in 2023, the amount of precipitation falling on days with the heaviest downpours has increased by 45% across the Midwest.
The 2010s were Wisconsin's wettest decade since record-keeping began around 1900. Between 2010 and 2019, the state experienced at least 21 "100-year" rainfall events, meaning a 1% chance of the event occurring in a given year.
Milwaukee's weather records date back to 1871, Vavrus said, and since then there have only been 11 days where the city has seen more than four inches of rain. Seven of those have occurred in the past 30 years. The National Weather Service reports that some parts of Milwaukee received more than a foot of rain during this last weekend's storm, which would shatter the state's 24-hour rainfall record if verified.
Vavrus also pointed back to the 2018 floods in Dane County, when torrential rains of more than 10 inches pummeled the area, killing a motorist and causing more than $150 million in damage. Both that storm and Milwaukee's recent one dumped "hurricane-like" rainfall amounts, he said.
"If people's perceptions are that these extremes are getting more common," Vavrus said, "they're exactly right."
It's a trend that scientists expect to continue if more effort isn't made to counter climate change.
Madeline Heim covers health and the environment for the Milwaukee Journal Sentinel. Contact her at 920-996-7266 or mheim@gannett.com.
This article originally appeared on Milwaukee Journal Sentinel: Milwaukee, Wisconsin seeing more intense rains due to climate change
Solve the daily Crossword
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Boston Globe
an hour ago
- Boston Globe
Floodwaters from a glacier near Alaska's capital city break record levels and prompt evacuations
Get Starting Point A guide through the most important stories of the morning, delivered Monday through Friday. Enter Email Sign Up The river hit major flood stage at 6 a.m. local time, already surpassing last year's record flood level of nearly 16 feet (5 meters), and was expected to peak at 8 a.m. before flood waters receded throughout the day Thursday, the National Weather Service said. Advertisement Basin flooding is a yearly worry Flooding from the basin has become an annual concern since 2011, and in recent years has swept away houses and swamped hundreds of homes. Government agencies installed temporary barriers this year in hopes of protecting several hundred homes in the inundation area from widespread damage. The flooding happens because a smaller glacier near Mendenhall Glacier retreated — a casualty of the warming climate — and left a basin that fills with rainwater and snowmelt each spring and summer. When the water creates enough pressure, it forces its way under or around the ice dam created by the Mendenhall Glacier, enters Mendenhall Lake and eventually flows down the Mendenhall River, as it did Tuesday. Advertisement Before the basin began overtopping, the water level was rising rapidly — as much as 4 feet (1.22 meters) per day during especially sunny or rainy days, according to the National Weather Service. The city saw successive years of record flooding in 2023 and 2024 — with the river last August cresting at 15.99 feet (4.9 meters), about 1 foot (30 centimeters) over the prior record set a year earlier — and flooding extending farther into the Mendenhall Valley. This year's flooding was predicted to crest at between 16.3 and 16.8 feet (4.96 to 5.12 meters). Last year, nearly 300 residences were damaged. A large outburst can release some 15 billion gallons of water, according to the University of Alaska Southeast and Alaska Climate Adaptation Science Center. That's the equivalent of nearly 23,000 Olympic-size swimming pools. During last year's flood, the flow rate in the rushing Mendenhall River was about half that of Niagara Falls, the researchers say. Before the basin began overtopping, the water level was rising rapidly — as much as 4 feet (1.22 meters) per day during especially sunny or rainy days, according to the National Weather Service. Becky Bohrer/Associated Press A temporary levee is installed City officials responded to concerns from property owners this year by working with state, federal and tribal entities to install a temporary levee along roughly 2.5 miles (4 kilometers) of riverbank in an attempt to guard against widespread flooding. The 10,000 'Hesco' barriers are essentially giant sandbags intended to protect more than 460 properties completely during an 18-foot (5.5-meter) flood event, said emergency manager Ryan O'Shaughnessy. Advertisement The U.S. Army Corps of Engineers is at the start of what's expected to be a yearslong process of studying conditions in the region and examining options for a more permanent solution, such as a levee. The timeline has angered some residents, who say it's unreasonable. Outburst floods are expected to continue as long as the Mendenhall Glacier acts as an ice dam to seal off the basin, which could span another 25 to 60 years, according to the university and science center researchers. Associated Press writer Becky Bohrer in Juneau contributed to this report.
Yahoo
an hour ago
- Yahoo
Record glacial flooding threatens Juneau, residents urged to evacuate
One of Alaska's most populated cities is bracing for potentially catastrophic flooding as a basin dammed within the Mendenhall Glacier has started to release rainwater and snowmelt downstream, according to officials. Suicide Basin, a side basin within the Mendenhall Glacier that sits above the city of Juneau, regularly releases glacier lake outburst floods, according to the National Weather Service. But recent measurements of water within the basement suggest the basin could release enough water to overwhelm the Mendenhall River and Mendenhall Lake, according to officials. MORE: Scientists concerned 'rare' glacial flooding event in Alaska could happen again By 7 a.m. local time, the Mendenhall River had reached a major flood stage at 16.51 feet and was continuing to rise -- surpassing the record flood stage set in 2024 of 15.99 feet, according to the NWS. Flood warnings have been issued for the lake and river due to the release. Residents along the flood zones have been urged to evacuate the area, with the peak flooding expected Wednesday around 8 a.m. local time. "Don't Wait. Evacuate TONIGHT," the City of Juneau wrote in a Facebook post Tuesday night. City officials were warning residents early Wednesday to avoid driving on roads within the flood zone already inundated by water. MORE: Massive, 18-mile-long Patagonia glacier experiencing rapid ice loss for 1st time Alaska Sen. Lisa Murkowski posted to X on Wednesday, warning of how dire the situation could become. "This is likely to become a life-threatening situation," Murkowski said. "If you are told to evacuate, stop what you are doing and immediately go to an emergency shelter or another safe location." Floodwaters are expected to fall below the flood stage through Thursday, according to the NWS. Mendenhall is a popular tourist attraction in Alaska, but the retreating glacier -- which acts as a dam for Suicide Basin -- has caused flooding in the region every summer in recent years after it refills with water from rain and melting snow in the spring. MORE: Why glaciologists believe the Birch Glacier collapsed, burying a nearby Swiss town In 2023, a glacier lake outburst at Mendenhall's Suicide Basin destroyed several structures along the Mendenhall River as the water rushed downstream. The record flooding prompted city officials in Juneau to issue an emergency declaration. The outburst, which caused a decade's worth of erosion in one weekend, would not have happened without climate change, NOAA said in 2023. Alaska has warmed twice as fast as any U.S. state over the last several decades, according to NOAA's National Centers for Environmental Information. Suicide Basin has been releasing glacier lake outburst floods since 2011, so the National Weather Service in Juneau's monitoring program has a camera pointed directly at the basin to see how much water levels are rising and falling. Record-breaking flooding from Suicide Basin also occurred in 2024, which damaged nearly 300 homes, The Associated Press reported. Glaciers in Alaska have been experiencing a steep decline since the late 1980s, according to the state's Department of Geological and Geophysical Surveys. MORE: Severe flooding from Alaska glacial break would not have happened without climate change, scientists say Globally, glaciers are at risk of significant ice loss due to climate change, scientists say. Glaciers around the world lost an estimated 7,211 billion tons of ice between 2000 and 2023, equating to an average annual loss of 301 billion tons, according to a Nature study published in February. The rate of ice loss has increased by about 36% in the past two decades, the researchers found. Even if warming were to stabilize at current levels, the world's glaciers would still likely lose at least 39% of mass, according to the World Economic Forum.
an hour ago
Glacier lake outburst at Alaska's Mendenhall Glacier causes record-breaking flooding
One of Alaska's most populated cities is bracing for potentially catastrophic flooding as a basin dammed within the Mendenhall Glacier has started to release rainwater and snowmelt downstream, according to officials. Suicide Basin, a side basin within the Mendenhall Glacier that sits above the city of Juneau, regularly releases glacier lake outburst floods, according to the National Weather Service. But recent measurements of water within the basement suggest the basin could release enough water to overwhelm the Mendenhall River and Mendenhall Lake, according to officials. By 7 a.m. local time, the Mendenhall River had reached a major flood stage at 16.51 feet and was continuing to rise -- surpassing the record flood stage set in 2024 of 15.99 feet, according to the NWS. Flood warnings have been issued for the lake and river due to the release. Residents along the flood zones have been urged to evacuate the area, with the peak flooding expected Wednesday around 8 a.m. local time. "Don't Wait. Evacuate TONIGHT," the City of Juneau wrote in a Facebook post Tuesday night. City officials were warning residents early Wednesday to avoid driving on roads within the flood zone already inundated by water. Alaska Sen. Lisa Murkowski posted to X on Wednesday, warning of how dire the situation could become. "This is likely to become a life-threatening situation," Murkowski said. "If you are told to evacuate, stop what you are doing and immediately go to an emergency shelter or another safe location." Floodwaters are expected to fall below the flood stage through Thursday, according to the NWS. Mendenhall is a popular tourist attraction in Alaska, but the retreating glacier -- which acts as a dam for Suicide Basin -- has caused flooding in the region every summer in recent years after it refills with water from rain and melting snow in the spring. In 2023, a glacier lake outburst at Mendenhall's Suicide Basin destroyed several structures along the Mendenhall River as the water rushed downstream. The record flooding prompted city officials in Juneau to issue an emergency declaration. The outburst, which caused a decade's worth of erosion in one weekend, would not have happened without climate change, NOAA said in 2023. Alaska has warmed twice as fast as any U.S. state over the last several decades, according to NOAA's National Centers for Environmental Information. Suicide Basin has been releasing glacier lake outburst floods since 2011, so the National Weather Service in Juneau's monitoring program has a camera pointed directly at the basin to see how much water levels are rising and falling. Record-breaking flooding from Suicide Basin also occurred in 2024, which damaged nearly 300 homes, The Associated Press reported. Glaciers in Alaska have been experiencing a steep decline since the late 1980s, according to the state's Department of Geological and Geophysical Surveys. Globally, glaciers are at risk of significant ice loss due to climate change, scientists say. Glaciers around the world lost an estimated 7,211 billion tons of ice between 2000 and 2023, equating to an average annual loss of 301 billion tons, according to a Nature study published in February. The rate of ice loss has increased by about 36% in the past two decades, the researchers found. Even if warming were to stabilize at current levels, the world's glaciers would still likely lose at least 39% of mass, according to the World Economic Forum.
