The ice is never safe. There is always thin ice somewhere.

I have spent most of my adult life on the ice every winter, every day I could get on it. I sail ice boats. I ski on the ice. I fly wings on the ice. I am also a former Navy diver with some experience in cold water and I have rescued a few folks, too. I have fallen through the ice more times than I can remember and rescued myself.

Ice sheets are rarely uniformly thick even in the middle of winter. There is always thin ice somewhere. Each lake or pond is unique. Varied environmental conditions can affect the ice differently in each place.

Some lakes and ponds have seasonal holes, which always appear in the same place under the same conditions. Knowing local conditions is important. But some lakes are persistent about surprising ice explorers. River ice or ice with current under it should be avoided because it is likely to be the most unstable and unpredictable ice.

Warm currents will melt strong ice from underneath while air temperatures remain below freezing.

Typical holes are influenced by underwater springs, a shallow area where the sun can heat the bottom through the ice, streams and currents. All are affected by temperature, water levels and sunlight. It is important to pay attention to local weather history so you know how long it’s been cold or how much warm rain fell.

Fluctuating water levels can leave thin ice bridging air. Thin ice without water to support it is common along pressure ridges and the shoreline, and disguised by a thin cover of snow can create traps.

Pressure ridges form on big ice when the ice sheets expand and contract. Along pressure ridges it is typical to find working open leads and thin ice even at low air temperatures. Pressure ridges are likely to form year after year in the same places when they are influenced by the geometry of the shoreline.

In shallow bogs, often swamp gas bubbles can be persistent enough to maintain holes. Air trapped within a quick freezing slush sheet can also insulate ice underneath and create a trap combined with a snowdrift that can further insulate thin ice.

Flocks of birds can keep the ice open in the early season where they are swimming. Wind can keep holes open by creating current, as well as waves, which inhibit freezing.

Deep water can also keep the ice from forming due to turnover. Water is most dense at 39 degrees. In spring and fall lakes and ponds turn over as 39 degree water falls to the bottom of the water column.

Snow insulates the ice. As little as an inch of snow can keep the thin ice underneath from freezing as fast as it would if the ice were exposed. Vestigial snowdrifts frozen into an ice sheet can create pits of slush in the spring, which you might plunge through even though the surrounding ice is strong. Snow also disguises hazards because you cannot see the ice through the snow. Heavy snow weighs down the ice sheet, causing water to flood through holes and cracks. The resulting slush under an insulating layer of snow can trap vehicles. If the ice froze before winter turnover, snow can insulate an ice sheet, which will melt from underneath as well as from warm water trapped on top beneath the snow.

Ice subjected to fluctuating temperatures above and below freezing can change structure so it is like honeycomb. In the spring, thick ice will melt fast as water is allowed to migrate through the ice within the tight vertical structure. It is possible to plunge through thick ice, which has gone to vertical crystals. Early in the ice season, black ice subjected to temperature fluctuations above and below freezing can also be very weak compared with new black ice, which has remained below freezing. As a general rule black ice is stronger than snow ice, but any type of ice subjected to enough temperature cycles above and below freezing can transform from a strong plate to a weak plate. I have sailed in an international iceboat regatta in Finland on a sheet of new black ice barely an inch and a half thick. The boats created waves in the ice sheet you could see and feel when they went by. I have also gone through old black ice that was 4 inches thick because it had been weakened.

Heavy rain causes drain holes in the old ice when water trapped on the surface of the ice tries to find a way to the water underneath. It usually takes at least 24 hours of hard freezing to really heal drain holes. Drain holes often are the first places the old ice will start to open up in the spring.

Checking the ice and observing the local conditions will help you as the season progresses. You will know where the spring holes were after they have healed in mid season, and by spring, potentially the same springs will open the ice first.

Downwind from large open holes the ice can be busted into smaller sheets by wind and waves, creating a nasty rough area defined by plates frozen on edge after the jumbled pieces are allowed to freeze back together. In the spring or during a strong thaw the jumbled ice pieces are not as strong as a single plate and they can be another place on an ice sheet that will melt early and should be avoided.

Check the ice carefully before you trust it. I use an ax with marks on the handle every inch starting about a half-inch from the head of the ax. Use your own judgment and trust your instinct.

If you don’t think it is worth trusting the ice, then don’t. When in doubt don’t. The best way to avoid going in is to check the ice carefully and never trust another person’s report until you have verified it for yourself.

If you can plunge the back of an ax head through the ice it is not going to be strong enough to support you. The way the ice cracks under load can tell you a lot about how strong it is. It is foolish to rely on color or thickness to gauge whether the ice is strong enough. Specific observation is the best way to find out.

Cracks are actually a good sign, but not the cracks that radiate from your ax or you when you step on thin ice. Cracks form in the ice due to pressure from freezing as the ice gets thick. As a general rule, I like to see the surface of new black ice start to crack into plates before I get on it. You can see that the surface of the ice is no longer perfectly flat or optically correct like a mirror.

Carry picks so you can rescue yourself and have a whistle so you can warn others and summon help. Carry a rescue line and an ice screw. Have warm clothes you can get into after you get out. I carry puff pants and jacket in a waterproof bag. Plan ahead and use a buddy system.





Rescue/ Self-Rescue

Only someone very strong can survive for long in cold icy water. All ice explorers must have the ability to rescue themselves and rescue their buddy.

Carry picks properly deployed tight under your collar so they won’t get flung behind your neck or tangled in your clothes where you can’t get them. Picks are hard to get from a frozen pocket.

Use a whistle.

Carry a throw line.

Most folks fall into holes relatively close to strong ice. Using the buddy system means that you will be close enough to ensure you can throw a line to your buddy from strong ice before it’s too late. When you go in, time is crucial. Within the first minute you will be shocked and surprised. Try to calm down and if you are not out with your picks right away, catch your breath, try not to drown, assess your position. Fear is the mind killer; panic will not help you.

Turn around to the direction from which you came. Get out as fast as you can and usually the best ice will be the ice you came from. Use the picks. Try to stay flat and pull yourself horizontally. Get flat on the surface and kick with your legs as well as using your arms, picks or not, to get back onto stronger ice. When you are out, remain flat on the ice and roll or pick your way to stronger ice where you can crawl and ultimately stand.

Get out, take off your clothes and wring them out, put them back on, if you don’t carry warm clothes in a waterproof bag, and make your way back. I know of one person who carries a spare Tyvek suit; wind chill is really nasty when you are soaking wet, so such a garment could help a lot and keep your clothes from freezing hard. Frozen zippers and buckles do not work very well.

If your buddy goes in …

Throw lines or rescue reels are a nice tool if you can deploy them quickly. Time is crucial. If you do not throw the rope in time, it is possible that your partner could be cold enough that he or she will not be able to grab a rope. I have seen this personally. An ice screw is a very useful tool to anchor the end of your line to strong ice.

Do not recklessly endanger yourself to try and save someone only to create a situation compounded by you being another victim trapped in the ice. It takes a little while for most folks to get so cold that they can’t react to thrown lines or a ladder. Try hard to talk your buddy into a self-rescue and use every available resource you have before you endanger yourself. Using the buddy system you should not be so far away that you can’t rescue your partner in time. Body type and physical fitness play a huge role in determining how long someone will be able to stay in the water without losing the ability to grab a rope. Use your cell phone to call for help. Be specific and detailed about the situation so rescue personnel won’t waste time; include best launch point to ice, victim location and ice conditions.

Throw ropes can freeze and be useless if they are allowed to get wet when it is cold enough. I use a reel carried inside my coat where it stays warm and does not get wet unless I go in. The reel also has the added advantage of being rolled instead of thrown, and I can roll mine much farther than I can throw a bag accurately. Reels work better than throw bags.

Common sense prevails. It is possible to skate or sail fast enough to be way out on very thin ice before you go in. A long rope will be the best tool if deployed fast enough. An inflatable aid will also work.

If you are that person on thin ice you know what they say. Skating on thin ice is completely avoidable because you should have checked. Thick rotten spring ice is a lot like thin ice. Temperatures below freezing can temporarily set up the surface of thick rotten spring ice so it is strong enough to sustain you until sunshine and rising temperatures weaken the ice. It gets weak very fast! It is possible to plunge right on through very thick ice over a foot thick when it has transformed; I have done this.

Do not expect to be able to self-rescue as easily if you are wearing an auto inflatable life jacket. An inflated vest can make it tough to be flat and horizontal and to be able to use your picks; an inflated vest on your chest will also catch the edge of the ice, making it hard to get out. An inflatable life jacket will float you after you lose consciousness, however, and keep you from drowning. The best way to avoid the holes in the ice is to check the ice and use good judgment so you don’t go swimming.

Check first, skate slow and watch the ice if you are at all unsure about it. When in doubt don’t. Be very wary of ice disguised by snow.

Sometimes here in Maine my friend Scott takes a tube used for sledding with a long line tied to it to tow the children. It is also a great rescue option. The tube can be towed easily behind a boat or a wing or by a skater. It can be slung to a person trapped in the ice and they can get out. It can hang out on the ice near where everyone is sailing. The tube is a mini raft in an emergency.

A survival suit is heavy and bulky and is not likely to be carried out very far onto the ice. By the time you go back to the car and get yours, it may be too late. If there is a large group, of course someone can go get the suit, but someone else should be rescuing the one trapped in the ice. A survival suit is nice to have on site but common sense and checking the ice properly are the best tools to use to avoid going in.

At a minimum everyone should have picks. I have gone in and been shocked by how hard it is to get out without them. In rotten ice you often plunge into a very small hole that will not allow you to get horizontal; you will need the extra help from picks. Black ice can be very slippery and will often break into plates around you. With picks it is possible to slither across a broken plate of ice that would not sustain you if you stood up, because while you are partially in the water, your weight is better distributed. Even a broken plate will give you enough purchase with picks to get back to stronger ice. I have been adequately supported by a plate of ice less than 4 inches thick approximately 4 by 5 feet around.

Be prepared; always carry picks!

Richard Saltonstall lives in Rockport.