It has been rather quiet around Lake Metigoshe recently. But I have been able to enjoy ice music occasionally. As some of you know, once a body of water has frozen over and temperatures drop, the big ice making machine can produce some interesting music. These concerts occur mostly during the evening hours when temperatures drop considerably. They can also occur during the morning hours when the sun comes up and temperatures quickly rise.
Ice, like other solids, contracts when it gets colder. As it gets colder, and begins to contract, tension can increase within the ice sheet. If the body of water is completely frozen over and frozen to the shoreline, that contractive tension can build to the point where the sheet of ice cracks apart. That releases the tension and sends soundwaves reverberating through the air above as well as the water below. Some people just call it the sound of ice cracking. Others call it ice music, or perhaps the ice symphony. Whatever the terminology, it is an interesting mix of sounds, all of them interesting, e.g. cracks, booms, bangs, thuds, reverberations.
It has been estimated that a 9 degree drop in ice temperature would shorten a mile of ice by 8.5 inches. No wonder lakes are often cracking during the winter months. And of course, those cracks can fill with water, freeze, expand, and increase the pressure all over again. Similar things can happen with a sheet of ice when temperatures rise quickly and the ice expands. All that contracting and expanding, melting and freezing, can cause the ice to buckle up, forming what we generally refer to as pressure ridges.
As most ice fishermen and snowmobilers know, pressure ridges can pose real danger to traveling across the ice. Small lakes do not pose much of a problem. But large lakes, such as Devils Lake, Lake Ashtabula, Lake Sakakawea, and Lake Darling are well known for occasionally producing large pressure ridges. Some of the big northern Minnesota lakes such as the Red lakes, Leech Lake, Lake of the Woods, and Rainey Lake can produce monstrous ridges.
I can’t help but wonder what early cultures thought of these sounds associated with large lakes during the winter. No doubt some cultures associated them with the spirit world.
The best time to try to take in this show is often mornings or evenings when temperatures are rising or falling rapidly. You really owe it to yourself to take in this show at least once. Grab a front row seat, get comfortable, and enjoy the show!
~Chuck Lura
