Goodbye river ice

PHOTO BY GARRY BRANDENBURG Ice breakup on the Iowa River is or has happened just about everywhere along the 29 miles of its travel through Marshall County. Recent warm weather assisted in weakening the ice, which was followed by one inch of rain last Monday. Now this week's January thaw warm air has completed the breakup of river ice. Withlots of winter still to come, a new cold spell of weather could cause new ice to form again. Only Mother Nature knows her next moves on this issue.

RIVER ICE has broken up due to the January thaw warmer than average air temperatures over the past week. It is just one of those cycles of nature that we humans get to see, experience and think about. January “thaw” is a term that people for well over a century have placed on a mid winter warm spells. So what would we call a mid-February winter “thaw,” a late January thaw? Just kidding. And when the month of March comes our way, we expect at least some increased average warming due to the earth’s orbital position with respect to the sun. The northern hemisphere begins to receive increasing amounts of light as we get nearer to the first day of spring on March 20.

While the river ice was here, formed by intense cold a few weeks ago, ice grew to be about eigh inches thick on average. Of course river ice may look smooth on the surface, but its thickness actually varies quite a bit due to flowing water under the ice. Be that as it may, once the river locked up, and new snow fell on the land and the river ice, a white smooth surface existed for a brief time.

From the Iowa Veterans Home regions of the river upstream into Hardin County, the river became a snow machine highway of extraordinary condition. Its smooth snow covered surface, wide and relatively straight course relatively free of tree snags, allowed those folks with snow mobiles to open the throttle as they cruised along at high speed. This most excellent snow mobile “trail” of the channelized portions of the Iowa River was nice while it lasted.

In contrast, the river downstream from Marshalltown is full of bends and curves as it meanders across the floodplain. Every bend has its deep cuts on the outside of a curve and corresponding sand bars that formed on the inside bend of each turn. This change in river flow rates, in part, allowed open water to stay that way while ice formed along quiet edges. Snow machine operation on this segment of the river was not going to happen.

Treated and clean waste water discharge from the Pollution Control Plant adds a few degrees of temperature to the river water. Thus, those few extra degrees helps to keep a long stretch of open water all the way toward Furrow Access and Three Bridges Park. Now add our recent thaw to the equation, plus any upstream ice breakups that allowed more chunks of ice to break free, and the stage is set for the river to lose its entire covering of ice.

River ice break up flowing freely toward pinch points may cause the ice to stall, not flow past or under the block point, and that is when we will see ice blocks accumulating sometimes for miles. Water under this jumble of broken and decaying ice still flows, eating away slowly by surely at the undersides of the ice. The river water level can and will rise taking the ice jam with it to higher and higher levels. This ages old scenario will play out in a couple of ways. First, a cold turn to the weather may not allow the ice blockage to deteriorate. Water rising due to ice jams can cause flooding in the valley. Or secondly, what we experienced this week was the opposite of cold, warm air, the few ice jams broke free without a flooding event.

The ice blockage at Furrow Access and the county road bridge on East Main Street Road, where today’s image was made, did not last. It melted enough to allow ice to ride the current downstream. Each bump and grind of the ice made each ice flow a bit smaller and smaller until little was left. On area ponds, our warm weather spell is also cause for caution. Ice gets rotten, less dense, and weaker as surface warm air and standing water on top deteriorate this ice. Do not assume the ice is safe to walk on if you like to pluck bluegills or crappies out of the pond. Have safety gear available to avoid a mishap.

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Elsewhere on planet earth, EARTHQUAKES and VOLCANOES tell us that our restless earth is just going about its business of growth, renewal and reshaping. Near the coast of Kodiak Island in Alaska, a 7.9 magnitude earthquake got lots of attention earlier this week. A precautionary tsunami warning was issued for a large region of north Pacific coastlines. It was later determined that blocks of earth’s crust had slipped past each other horizontally, not vertically, and therefore no large displacement of water took place to form a large ocean wave.

The Pacific Ocean “Ring of Fire” is an active geological phenomenon. Around its edges where one tectonic plate of the earth slowly and unstoppable slips under the lighter crustal rocks of an adjoining continent, rocks deep down get pushed, squeezed or stretched in tremendous ways. And when the stress reaches to a high enough level, something has to give. And give it does in the form of an earthquake. Rock blocks of earth’s crust scrape past each other up or down, or side by side in a variety of ways. However it occurs, rocks breaking from plate tectonic movements make the earth shake under our feet.

The “Ring of Fire” also is the origin for many weak points in the crust that allow lave to escape upward. In the Philippine Islands, Mount Mayon burped this week, sending molten lava down its mountain top slopes. At night it was an awesome sight, but a potentially dangerous sight, to know that the possibility exists for a full fledged ash cloud and lava flows to inundate lands where lots of people live. In comparison, Iowa’s winter storms of strong winds, heavy snow falls, or our summer heat waves and possible tornadoes, all seem like pretty small potatoes. Mother Nature in her awesome raw beauty and power reminds us that she is in charge.

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HUNTING SEASONS are winding down Investigations by game wardens are not winding down. The Iowa TIP hotline (1-800-532-2020) still lights up as suspected poaching cases get details added from many sources. Game wardens check our all leads to see what the bad guys did or are still doing. TIP is the acronym for Turn In Poachers that is available to Iowans either via the phone or website or as direct calls to a conservation officer. Approximately 100 cases are logged into the website every year. Not every call ends up being a “big” investigation. However, every call is important because the information may be a missing piece of the puzzle that take a little case and turn it into a multi-state investigation.

Some TIP cases end up offering monetary rewards to the person or persons who made the contact resulting in successful prosecution in court. Reward amounts are based on an individual case-by-case basis. And many time the person, usually another hunter or fisherman, will decline the monetary award. Their reward was knowing that the bad guy got arrested, his gear confiscated, hunting privileges revoked, or even jail time. It is good that lots of people are concerned enough with proper ethics in outdoor sports activities to conduct themselves properly by following the law. When they see improper, illegal, greedy or wasteful use of natural resources, it is easy to call those infractions into the Iowa TIP hotline.

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Coming up soon, on the evening of Feb. 7, at the Fisher Community Center, our local IZAAK WALTON LEAGUE will host their annual WILD GAME SUPPER. Members and guests will bring specially prepared dishes of venison from deer, elk, moose or bear, plus fish meals of walleye, salmon, crappie, catfish or other. Self-serve lines on long tables with labeled crook pots of warm delicious meats will tempt your pallet. Meal time will be 6 p.m., with a program at 7 p.m.

Speaker for the evening Ikes program following the wild game supper will be our local Conservation Officer Tyson Brown. He will show a power point program on the work of Iowa game wardens and answer questions about how his law enforcement training is used in day-to-day work. All Ikes members, active or once active, your family and guests you want to invite are welcome to attend. You will have great food to choose from, great friends to visit with, new friends to make, plus the opportunity to learn from a conservation officer what it takes in this specialty side of fish and game law enforcement.

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Did you know: In the United States and Canada, wild harvested game and fish as sources of sustainable protein for people to eat and survive is huge. It is estimated that between 35 and 40 million people rely solely on wild game and fish to live. How would society replace this vast amount of organic food if hunting or fishing was not available? It is an important question that goes to the heart of why conservation of natural resources is critical to all Americans and Canadians. We need hunters. We need fishermen. We need these protein sources from nature.


Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at PO Box 96, Albion, IA 50005.