It’s rare that Minnehaha Falls truly freezes completely. Even in the coldest winters, when you climb up behind the waterfall you can hear the trickling of moving water. Sometimes you can see the water moving through the ice.
The lip of the waterfall is more narrow than it used to be, and indeed has been getting narrower in the last 10 years with erosion. But every winter we see a wide curtain of icicles all across the western side of the Minnehaha Gorge. They are created by groundwater moving through the limestone layer that creates the lip of the falls. Starting in 1889, the Park Board has done a lot of work to de-water springs and redirect that groundwater, and much of that work has been successful. But the icicles still form.
The Great Depression. Something like 25% of the work force had no jobs. Soup kitchens provided a hot meal, maybe the only one these people would get. Work relief programs were started by the presidents of the day, Hoover and then Roosevelt. These job-creation agencies worked on America’s infrastructure. And someone named Walter B. Dahlberg, possibly an employee of the parks, compiled some terrific reports on the works accomplished in the Minneapolis park system. These are available on-line for 1936-1942. (Perhaps any earlier reports were lost, or haven’t been put on-line yet.)