Mayflies cause 3-car crash in western Wisconsin


Swarms of mayflies made for slick road conditions Sunday night, causing a three-car crash in western Wisconsin.

Mayflies are mostly harmless – they don't bite or sting – and they only live for about 24 hours. But after mayflies hatch, they can swarm together in gray clouds that can be a real nuisance, and even an occasional danger to drivers.

Millions of mayflies swarming together can create visibility problems on roads, and make things slippery when they fall to the ground and all die in the same spot, FOX 9 reports.

In the past, cities including Trenton, Wisconsin, and Red Wing, Minnesota, have used snowplows to clear roads of inches-deep mayflies, the Pioneer Press reports.

That's what happened Sunday, when a mayfly-covered road caused Theresa Hunt, 24, of Ellsworth, Wisconsin, to lose control while she was driving northbound on Highway 63 around 10:30 p.m., the Pierce County sheriff's office said in a news release.

Hunt crashed into two other cars, injuring one passenger, who was taken to Mayo Hospital in nearby Red Wing, according to the release.

The Pierce County Herald reports a highway department employee responded to the scene with a plow-equipped maintenance truck to scrape and sand the slippery, mayfly-covered road.

A county official told the newspaper there were a lot of mayflies in the area Sunday night, but nowhere near as many as in July 2004 when mayflies caused a multi-vehicle accident and closed Highway 63 for several hours while the flies were plowed away.

It's currently mayfly hatching season in the Midwest. News 8000 has photos of a recent mayfly hatch in La Crosse, Wisconsin. The hatch was so thick it could be seen on weather radar maps.

Although they're bothersome to many, it's a good sign if mayflies are around. The bugs can only reproduce in areas with high-quality water – the amount of mayflies in a hatch correlates to the health of nearby lakes and rivers, FOX 9 says.

Next Up


Pandemic pushes need for cybersecurity and I.T. professionals to forefront

University of Wisconsin-Superior is helping meet demand with online master’s programs

Screen Shot 2020-12-03 at 5.01.58 PM

Body found floating in Minnesota River in Shakopee

Efforts to identify the deceased are underway.

Hennepin County Government Center

Judge finds suspect guilty in 1991 murder of young Minneapolis woman

A 58-year-old man from South St. Paul, who was 29 at the time, has been found guilty of stabbing a 20-year-old woman

northfield community education center

Northfield school fires employee who allegedly gave melatonin to infant

It's against district policies to give a child anything without a parents' permission.

state hockey tournament, mshsl

MSHSL approves 3 calendars to start winter sports as soon as Dec. 21

The start date will depend on whether the state shutdown is lifted.


Drug overdose deaths up 31% in the first half of 2020

Overdose deaths started to increase sharply in March, which coincides with the state-ordered lockdown for the COVID-19 pandemic.

los ocampos

Video: Vehicle crashes into St. Paul restaurant

The fire department is on scene addressing a gas leak.

covid-19, coronavirus

Latest county infection rates are sky-high throughout Minnesota

Kandiyohi County is one of the hardest hit counties in the state.

Jenna Fish

Family's warning after teen's tragic death from CO poisoning at Thanksgiving

A 17-year-old girl from Delano died after Thanksgiving due to carbon monoxide poisoning.


More than $12K donated to MN gym owner who refused to close

The small business is located in town in Wabasha County.

radio station, microphone

MPR, The Current launch new weekly segment called 'The Warming House'

The program will feature feel-good entertainment amid the pandemic.