It’s Freezing! Facts about the Lakes in Winter

I thought I heard someone calling the other day. As I listened closer, it was the lake softly whispering, “Don’t forget me. I can still be fun, even in winter.”
Every season brings its own blessings and trials, and winter is no different. Branch County’s lakes offers their own share of pleasures … and dangers. With just a little understanding of lakes in winter, you can discover a whole new way to enjoy what your lake has to offer while it is frozen over.

It has been a while since I have played on the ice, but when I was a kid I was out there with my dad every winter. He loved to ice fish and I liked to ice skate … a win-win situation. So many folks partake in ice fishing, ice skating and other winter activities on the ice without really understanding the basics of being on the ice.

LAKE FACTS IN WINTER

All lakes and ponds have a routine, so to speak, on how they freeze. A body of water takes longer to cool down and longer to heat up than land. When an entire lake reaches 40°F, the surface water cools further, dropping below that temperature. Once the surface water reaches 32°F, it freezes and the freezing keeps spreading downward, thus making the ice thicker and thicker.

So why doesn’t a whole lake freeze? As ice crystals freeze, they float to the surface and as they become thicker, they act as insulation, preventing the cold air above the water from removing heat from the unfrozen water below. Because of this process, a lake never freezes solid from top to bottom. Water is shallower at the lake’s perimeter, thus, it freezes faster near the shore then moves toward the center.

So, what is considered a safe thickness of ice to be on the lake? That depends on how much weight you are planning to take on the ice. The Old Farmer’s Almanac recommends three inches of ice for a person on foot, four inches for a group walking in single file, seven and onehalf inches for a passenger car with a two-ton gross weight and eight inches for a light truck weighing two and a half tons. The almanac also stresses that slush ice is only half the strength of regular blue ice and the strength of river ice is 15% less than lake ice. Also, the thickness of a lake’s ice is different at different points, so it is recommended that you check it every 150 feet.

HOW LONG DOES IT TAKE A LAKE TO FREEZE?

How long it takes a lake to make the varying degrees of ice thickness depends on what is known as “freezing degree days.” The formula for this is quite simple: First, take the average temperature over the last 24 hours and subtract that number from the freezing point of 32°F. Ice will increase at a rate of one inch for every 15 freezing-degree days. For example, if the average temperature over the last 24 hours was 25°, subtract that from 32°, which will give you 7°. Put 7 over 15 like a fraction: 7/15 equals about a ½ inch of ice over a 24-hour period.

Keep in mind that these are only guidelines. This formula is based on having a slight to moderate wind speed, no snow on the ground and clear skies. These all help to pull heat out of the water and accelerate the growth of ice. Just because the thermometer says 32° does not always mean that water will freeze. The University of Utah chemistry department shows that water can get to –55° before it must freeze.

STRANGE PHENOMENA WHEN ICE FREEZES

Frozen lakes and ponds have some phenomena that they claim for their own when they are frozen over. Perhaps the most frightening for anyone who spends any time on the ice is the cracking noise. My dad always told me, “It’s just making more ice when you hear that noise.” It never made me feel any better, but it was essentially true. Ice expands or contracts when the temperature changes, thus causing cracks to form in the ice.

This same action of expansion and contraction causes lines on the frozen lake’s surface. We were recently down with our friends who live on Union Lake in Michigan and noticed these lines, with no particular pattern or reason, leading out into the lake. They are referred to as pressure ridges. Even when a lake is completely frozen, it is not stagnant; it still expands and contracts as it warms and cools. When it warms during the day, it expands, causing a collision between both sides of a crack and causing the ice to buckle up at that pressure point.

Ice heaves and ridges are caused by the pushing action of a lake’s ice sheet against the shore. When lake ice cracks, water rises into the cracks and freezes, gradually expanding the heave.

WHAT TO DO IF THE UNTHINKABLE HAPPENS

Frozen lakes offer opportunities to enjoy our water resources in the winter as well as summer. However, they offer their own set of risks. Besides the thickness of the ice, always beware of those who have been out before you. Specifically, I am talking about holes that ice fishermen have drilled and abandoned. You can easily step into one of these and trip … and a fall on the ice is a lot harder than on land! These holes also pose risks for ice skaters. I found out the hard way what happens when a skate catches an open hole.

As careful as one can be, ice is unpredictable and there is always that chance that if you play on a frozen lake you could find yourself plunged into its icy perils. If the dreaded does happen and you do fall through thin ice, the first thing to remember (and this is easier said than done) is not to panic. It is true that the physiological response to cold water shock and hyperthermia is pretty quick, but by keeping a level head and knowing what to do, you can save yourself.
Immediately put your arms and legs out to slow your descent. The first reaction is to try to claw your way out, but by doing this, your body weight and wet clothing may pull you back down. Many folks who have experienced the frozen lake waters have said they could not get a deep breath. This happens because when they panic, they forget to exhale first.

Use your behind to lift your lower body and then bring your legs up and extend behind you. If you have skates, snowshoes and even in some cases, boots, kick them off to dispose of added weight and anything that might “catch” on the ice when trying to pull yourself out.

Kick your legs softly to launch yourself forward on the ice then kick hard to propel yourself horizontally out of the water on your stomach. Do not stand, but rather, use your arms to pull yourself across the ice to where it is thick enough to support your weight, then get on all fours and crawl towards shore.

Lakes in winter offer a beauty and solitude that are not present in the other seasons. You are truly missing out if you don’t grab yourself some “nice ice time” on our lakes and ponds. Just know the basics so you can thoroughly and safely enjoy the lakes year-round.