Skip to main content

They're coming: Mayfly hatch expected along Mississippi River soon

Hastings is turning off the lights to "lessen the impact" of the mayfly hatch.

The city of Hastings is preparing for the first big mayfly hatch of the summer by turning off all the lights. 

Yes, that's right. The city starting Wednesday and continuing through the weekend will turn off lighting along streets and parking lots in the downtown area, on the bridge and along the riverfront to "help lessen the impact" of the insects, which can be attracted to bright lights during their short lives.

Mayflies can be found in almost all freshwater systems that have adequate oxygen levels (they're actually a sign that the body of water is healthy), and when its time to hatch the mayflies often do it all together, the Minnesota Department of Natural Resources website says

These large hatches are so big they have been spotted on weather radar.

Hatches happen a few times a year when mayflies emerge from the water, becoming adults only a few days later. Then they mate, the female drops her eggs back into the water, and then they die soon after, the DNR says. An adult mayfly rarely lives longer than a month.

Sometimes when they die, they all die in the same place. Their dead bodies can make roads slippery. And sometimes snowplows have to be called in to clear the dead bugs off the road. 

The city of Hastings, which is familiar with large mayfly hatches, says "Any mess on public streets and parking lot areas resulting from mayfly hatch activity will be cleaned up only during normal business hours."

Next Up

police tape

3 at trauma centers in critical condition after rural MN attack

Two victims and the alleged attacker are in critical condition.

grinch neighbor

Neighborhood 'grinch' sends letter to Burnsville family over holiday lights

A Burnsville family's holiday decorations were the subject of an anonymous complaint.


Anthropologie shutters Grand Avenue store, opening planned for Rosedale Center

The popular holiday shopping weekend marked the last for customers of the Grand Avenue store.

hospital, emergency room

Woman found on side of highway after hit-and-run

The 41-year-old was airlifted to a hospital with life-threatening injuries.

Jorden Nicole Borders

Charges: Minnesota woman tortured her kids, removed boy's blood

Warning: This story contains upsetting content.

first snow

Will narrow band of 6+ inches of snow hit Twin Cities Tuesday?

The NWS says a band of 6+ inches is looking likely. It's now a matter of where.


Siblings, ages 19 and 14, killed in crash on icy MN highway

The crash happened around 1:15 a.m. Saturday in Carlton County.

Nicholas Kraus

Man sentenced for fatally striking woman during Uptown protest

Nicholas Kraus, 36, of St. Paul drove into a protest in Uptown last year, killing Deona Marie Knajdek.

Flickr - police lights squad siren - Edward Kimmel

Fleeing suspect crashes into vehicle in Woodbury, 2 injured

The crash occurred Friday afternoon after a pursuit with Woodbury police.

Screen Shot 2022-11-26 at 2.34.44 PM

Yes, that's MN native Jenny Taft in a State Farm commercial

Jenny Taft got her broadcasting career started in Minneapolis in 2011.

crime scene tape - police tape

23-year-old woman critical after shooting in Plymouth

A 23-year-old woman was shot Friday night in Plymouth.

white Christmas

2 MN towns among most 'magical' winter locations in the country

The list was compiled by Trips Discover and published earlier this month.


Minneapolis trail 1

Minneapolis reveals plans for new trail along Mississippi River

The trail will connect the 26th Avenue North Overlook to Ole Olson Park.

garbage mississippi river

St. Paul launches initiative to track plastic, debris in Mississippi River

The City of St. Paul has teamed up with other communities to create the Mississippi River Cities and Towns Initiative.

old sartell bridge

Sartell wants to reopen historic bridge over the Mississippi to pedestrians, bikers

If it gets approved, the bridge could be open to pedestrians as soon as next year.

upper st. anthony falls lock and dam

Rare chance to see what the Mississippi River in Minneapolis used to look like

The Upper St. Anthony Falls Lock and Dam will be open to the public.


Mississippi River Learning Center to showcase St. Paul as 'the river capital'

The year-round destination planned for Crosby Farm Regional Park could open as early as 2025.

mississippi river 13

Photos: Rare drawdown of the Mississippi River in Minneapolis attracts hundreds

The river was about 12 feet lower than normal, exposing riverbeds and pieces of history.

Twitter - Mayflies St. Paul - Jay Xiong

It's mayfly season in Minnesota, and it's totally gross

But a mayfly hatch is actually a good thing, we swear!