Slush on the lakes is bad news for ice fishing
The lakes in the Bemidji area are frozen over, but the heavy snowfall has already created some slush problems on many lakes.
The ice is actually floating on the water in the lakes. When too much snow falls on the ice before the ice is thick enough to support the weight, the ice starts to sink and begins to ride low in the water.
The pressure from the weight of snow on the ice forces water out of any cracks or holes in the ice to relieve some of the pressure. The water begins to flood the surface of the lakes, especially where anglers have been drilling holes in the ice.
Snow has strong insulating properties, so it takes a significant amount of cold to penetrate through the snow and freeze the ice on the lakes.
When a layer of water begins to collects on top of the ice, the water gets mixed with the snow and creates slush. This slows down the freezing process even further.
When anglers drive ATVs, snowmobiles or vehicles on lakes with slush, they often break through the first layer of ice and can become stuck in the ice.
Fish houses on the lakes add weight to the ice. When anglers try to fish through the slush, the water can keep building up under the houses.
When the area around the fish houses becomes flooded with water, anglers need to block up their houses to prevent them from becoming frozen into the ice.
Blocks of wood can be placed in the corners of the house to help keep the houses out of the water, but the blocks have to be high enough to keep the house out of the rising water, or they will get stuck to the ice.
The bottom line is the heavy snowfall this early in the season can have a negative effect on the ice conditions all winter long.
The heavy snow and slush on the lakes brings up another risk factor for lakes prone to winter kill.
The slush and snow significantly reduces the amount of sunlight that is able to penetrate through the ice. Plant life in the lakes can keep making oxygen as long as there is sunlight and part of the plant stays green.
If there is not enough sunlight getting through the ice, virtually all of the plants in the lake will die.
When plants die in the lakes, they begin to use up oxygen instead of producing it while they decompose.
Nutrients in the water also use up oxygen as they break down, as do any fish or aquatic life that dies in the lakes.
Lakes begin the winter full of oxygen throughout the entire water column. The amount of oxygen in the lakes is finite and it can be used up over the winter.
The amount of water in the lake (water volume) has an impact on how much oxygen is stored in the lake.
Deep lakes and lakes with a large amount of surface area rarely run out of oxygen in the winter because they have more oxygen than they need to last all winter.
Some small shallow lakes are vulnerable to winter kill in years when plant life in the lakes dies early and is not able to keep making oxygen at least part of the winter.
When oxygen levels in the lakes get too, fish in the lakes start to die, which speeds up the burning of oxygen even faster.
Now that everyone hates slush, hopefully the lakes will have the chance to make more ice before adding more snow.
The best thing for the lakes right now is to get more cold weather to help add ice to the lakes and freeze up some of the areas with slush.
Anglers wanting to get out on the lakes will need to watch the ice conditions closely. Anglers may be able to travel on some lakes with ATV's and snowmobiles, but vehicle traffic on the ice is still weeks away.
Paul A. Nelson runs the Bemidji Area Lakes Guide Service. He can be contacted by calling 218-759-2235.