A combination of unseasonably warm weather and thick, solid ice left from one of the coldest winters of the 20th century resulted in record flooding of the Ontonagon River in early April 1963. On March 31, the temperature rose to 72 degrees, a welcome change after the area endured severe, consistent cold from early January into the first half of March. Trouble began quickly that day as heavy runoff from rapidly melting snow met with a solid ice pack on Lake Superior. In addition, river ice began to break apart. The first heavy ice flow came down the Ontonagon April 1 and jammed up against the railroad bridge. Heavy flooding swept over the entire island between the river and slough and then spread throughout the center of the village, spreading icy water from two to three feet deep.
Damage to property and businesses was extensive. Boat houses were demolished along with the watercraft in them. The boats were then swept into Lake Superior or wrecked by the ice, piled high on adjoining land. In area businesses, the water rose so fast there was no time to move or shift stock. Buildings on the south side of River Street were soaked with up to four feet of water. As the water receded, a thick coat of red silt mixed in places with oily substances was deposited over everything the flood touched. Truckloads of flooded food and other merchandise ended up in the village dump??a precaution taken to prevent the possible spread of waterborne disease.
The village slowly got back to normal as the water receded and found its way into Lake Superior; this despite a two-mile ice jam which still held on the lake. Conservative estimates of damage was placed at over a half million dollars.
The last big widespread U.P. flood occurred 12 years ago. Heavy rain fell on a thick snow pack in mid-April 2002 and was followed quickly by record warmth. This particular combination of weather elements is the worst for U.P. snowmelt floods.
Last year, there was moderate flooding as the warmth of late April was followed by more rain and snow and then more warm weather. This year, late-winter precipitation has been on the light side. However, a major snowstorm could affect much of Upper Michigan at the end of the week putting more water equivalent in the snowpack. The overall outlook is for below average temperatures. As long as the pattern doesn??t shift quickly to early summer major flooding should not be a problem.