Minnesota Bridges Going Dark Because Of Mayfly Swarms

RED WING, MN — Three Mississippi River bridges in southeastern Minnesota are going dark because of mayfly swarms, according to the Minnesota Department of Transportation.

MnDOT said crews will temporarily turn off overhead lights on the Highway 63 bridge in Red Wing, the Highway 60 bridge in Wabasha and the Highway 43 bridge in Winona.

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The lights will remain off until the mayfly hatching subsides, officials said. Mayfly hatches can often last for weeks.

Mayflies are attracted to lights, and large swarms can gather on bridge surfaces during hatching season. That can create dangerous driving conditions, especially at night.

Turning off the lights is intended to reduce the number of mayflies collecting on the bridges, MnDOT said.

There are four Mississippi River crossings in MnDOT’s District 6 in southeastern Minnesota. The Interstate 90 Dresbach bridge near La Crosse, Wisconsin, will keep its lights on because of interstate speeds, traffic volumes and the complexity of the interchange.

The other three bridges will be dark until the hatch eases.

MnDOT reminded drivers to slow down, stay alert and avoid distractions while crossing the bridges.