Prevent Ice Heaving & Ice Ridges on Your Shoreline, Caused by Ice Jacking (AKA Ice Expansion, Ice Push, or Ice Shove)
Want an ugly shoreline that crumbles and erodes? Then hire a landscaper. But if you’re way past looking for quotes and want a riprap shoreline that’s built once and built right by the best hands in the business, contact Lakeshore Guys today. Also, see this case-study on how our shorelines resist ice damage.
Your shoreline is a pleasant, relaxed place during the warmer months…if it makes it through the colder months intact.
The winter freeze and spring thaw together can ruin your shoreline. Ice heaving, ice jacking, and ice/pressure ridges are three distinct problems with the same outcome: a beat-up, heaved shoreline, at the very least. Some especially nasty ice heaves can even crash into your home, if it’s close enough to the water.
For the sake of your shoreline, you need to know about three ice-related, shoreline-devouring phenomena – explained below.
Windblown ice (sometimes incorrectly called “ice heaving”)
As the spring thaw progresses, the ice melts and breaks up. Because ice usually begins melting into open water along the shoreline, you now have a giant free-floating sheet of ice. Even slight winds can push this free-floating ice blob across the lake, bouncing from one end of the lake to another like an air-hockey puck.
Things get exciting if the wind blows the giant ice-raft toward your shoreline. It’s as easy to stop as a trainload of sumo wrestlers. Because ice becomes thinner and weaker along the shoreline, the shoreline ice begins to break up first, as it’s pushed by 100 tons of pressure from the massive (and much thicker) piece of floating ice farther out from shore. On a windy day the force will be even greater, creating enough pressure to break larger or thicker pieces of ice off at its edges and pile them up along your shoreline.
Soon you have a mountain of ice on your shoreline. With nowhere else to go, the main floating chunk of ice pushes into the earth along your lakeshore, and forms the smaller chunks into a pile. Unless you live on a very large body of water, windblown ice doesn’t typically cause ice ridges (AKA ice heaving or “shoreline buckling”).
But if you do live on a very large body of water, windblown (or wind-driven) ice can destroy anything in its path. It can push your home or cabin off of its foundation.
The good news is windblown ice is not a potential hazard every year. Also, it’s likely only a real concern if you live on a large lake, if the late winter / early spring thaw is slow, or if there are heavy winds in the early spring.
The solution: If you ever have experienced ice heaving (where you’re left with a heaved mound of earth along your shoreline in the spring) as a result of windblown ice – like what we’ve described above – you’ll want to ask us about our “Armored Shoreline.” Many studies have been done on preventing shoreline damage caused by windblown ice, and from those studies the DNR has developed a method to create an ice-heave-resistant shoreline. Our Armored Shoreline uses a DNR-approved design, but we don’t stop there. A DNR-approved shoreline is a minimum standard that a competently-built shoreline must meet.
Over the past 20+ years our shorelines have become the most ice-heave-resistant shorelines built. No shoreline is invincible, but our super-engineered design comes as close as you can get. It’s not cheap, so we don’t recommend this method unless you’re on a large lake, you’re on the windblown side, and you’ve had ice heaving in the past.
Pressure ridges (sometimes incorrectly called “ice ridges” or “ice heaving”)
Though pressure ridges rarely cause shoreline damage, they’re worth discussing because sometimes they do cause damage.
Ice forms throughout the winter constantly, especially when the snowfall is lighter. The sheet of ice covering the lake grows thicker and more pressurized every day. As the ice grows thicker, so does the pressure expanding both upwards, and to all sides (including against your shoreline). Because water expands when frozen, the thicker the ice, the greater the pressure exerted outwards on all sides. Also, because ice floats, the thicker the ice becomes, the more buoyant it is, so now you have upward pressure. Fun fact: if ice were to release all its pressure at once, there would be a giant explosion of ice flying in two directions: up into the air, and 360 degrees outwards (towards the shore).
Because the pressure increases as the ice grows thicker, it often shows itself in random areas on larger lakes. These ice speed-bumps are called pressure ridges (sometimes incorrectly referred to as ice ridges). They’re common, and typically pose no hazard to anyone (unless you happen to be zooming across the lake and end up in an unexpected Evel Knievel moment). But occasionally ice ridges appear immediately adjacent to the shoreline. The same pressure that created the ridges will drive them deeper into your lakeshore, tearing it up in slow-motion.
We haven’t observed a pattern as to where pressure ridges pop up along shorelines. But there is a slight tendency for ice ridges to form farther out into the lake, in areas where there is a significant change in water-depth within a short distance.
The solution: If you’re dogged by pressure ridges, ask us about our “Armored Shoreline.” We’ve developed a pressure-ridge-resistant shoreline. But in most cases pressure ridges are misdiagnosed, and the real problem is “ice-jacking.” (See below for more on ice-jacking.)
Ice jacking (sometimes incorrectly called “ice ridges” “ice heaving” “ice push” or “ice shove”)
Even worse is when the expanding ice pushes your shoreline in, up, and out of the way. In that case, the frozen sheet of ice was so thick that it was easier for the ice to expand and push your frozen shoreline out of the way than it was to break the increasingly thickening sheet of ice and push it upwards (causing an ice ridge). The ice had to expand somewhere, and your shoreline was the path of least resistance. Any shoreline design to “stop” the ice will fail every time. You don’t stop Mother Nature, but you can reason with her. (More on that in a moment.)
Ice jacking typically its worst in very cold winters with meager snow. Without a thick blanket of snow to keep the ice at a relatively constant temperature, the giant sheet of ice is easily heated and cooled by the fluctuating ambient temperatures or the sun, or both. The constant change in temperature causes increased expansion and contraction as the outside temperatures rise and fall, and as the sun goes up and down. When the temperature falls, ice contracts. That causes cracks in the ice, which quickly fill from the water below and refreeze. When temperatures rise, the ice expands. But now because the cracks have filled and frozen, the ice has nowhere to go, so it pushes up against the outer edges of the confines (i.e., the shoreline).
In every cold-warm cycle there is a ratcheting effect – hence the name “ice jacking” (think of the jack you use to change a flat tire). More and more pressure is put on the shoreline as the ice is slowly jacked towards the shoreline, inches at a time.
Note: Any substantial change in temperature (including the suns rays on a clear day) cause ice to crack. Assuming the ambient temperature is below the freezing point, those cracks quickly fill with water and refreeze. Cracks constantly filling with water and refreezing equates to an ever-expanding sheet of ice.
Ice-jacking is worsened if you go into the winter with higher-than-normal water levels. If the water is higher against your shoreline, the ice has even less room to expand before plowing up your shoreline. 2019 was an especially bad year here in Minnesota, because we had ultra-high water levels due to a wet spring, summer, and fall. Plus, we had no snow in December and January of 2019, combined with record-breaking sub-zero temperatures. And plenty of sunny, cloudless days. It was the perfect storm. The only saving grace was the heaps of snow we received in February, which insulated the ice like 3 feet of Thinsulate, stopping the ice expansion in its tracks. Still, all the damage had already been done.
Nothing will stop the expansion of ice. The pressure is too great. But that doesn’t mean there’s no solution.
Your best defense against ice heaving, ice jacking, and ice ridges is a strong, durable riprap shoreline. The key is to work “with” Mother Nature, not against her. If you happen to be one of the few shoreline property owners who’s consistently dealing with ice jacking, we recommend an ice-heave-resistant Lakeshore Guys® “Armored Shoreline.” Riprap stones, when built on the right grade at the proper slope, on tough fabric, and piled in just the right amounts, can shield your shoreline and the rest of your property better than anything else can. Although there is no guarantee that riprap will prevent winter damage in all cases, it’s your best option to guard against ice heaving and ice jacking.
Contact Lakeshore Guys® today to fortify your shoreline.