Holes In Ice

• Thawed Pressure ridges
• Warm Water Holes
• Gas Holes
• Drain Holes
• Lake Shore Holes
• Reef Holes
• Man made Holes
• Current Holes
• Spring Holes

The following is the first in a series of articles about holes. This article covers warm water holes and gas holes. Both are common early ice holes.

Warm water holes:

When the ice first freezes it usually does so during a cold snap in calm conditions. In many cases the bulk of the water is not really as cold as it should be to sustain a frozen surface. In this case there will often be holes from a few feet to a few tens of feet in dimension that do not freeze over until several hours to a couple of weeks after the main ice sheet forms. These areas probably stay open because of convection currents set up in the water by the large difference between the surface temp of the water under the ice and the water exposed to the very cold air above the holes. They often stay open for days or weeks because early season cold snaps are often followed by a period above freezing weather. Characteristics of warm water holes:

1. They form on water that is "not ready to freeze happily".
2. Are usually roundish in shape.
3. They are associated with first ice.
4. Often seem to be in groups.
5. They often have a ring of white ice on some or all sides from water that splashed out and froze.
6. When these holes do skin over they are typically one to 4 inches thinner than the surrounding ice.
7. They generally do not all freeze at the same time.
8. The hole edge is usually nearly full plate thickness to within a few inches of the edge .
9. They are very easy to spot from shore (ideally at a little elevation above the lake) on a sunny day with some wind to make the open water dark.
10. They do not tend to form in the same spot year after year.

Warm water holes are probably the second most common form of Holes. They are particularly insidious when they first skin over. This makes them very hard to see and gives the sailor no way to know how thick the ice is. We have generally found the only way to be sure they won't be a problem is to carefully check out the area we will be sailing. Observing the ice as it freezes will give a good idea of where to expect problems.

Gas Holes

At the second attempt to sail the 1986 NA regatta on Lake Honeye in western New York. Henry Bossett was sailing at speed to windward with several other sailors when he dropped a side runner into a gas hole. Henry was not hurt but his boat was destroyed. Luckily, it was not his front runner.

When we looked around there were holes and runner cracks all over the place in about a 100 yd by 200 yd area. The holes ranged from a couple to several feet in dimension with a circular shape. All of them had a stream of gas bubbles coming up from the bottom near their center. After the accident the sailors walked most of the lake and did not find holes other than this and another small area.

Gas holes are common in certain areas and unknown in most areas. They are caused by the steady release of marsh gas from the lake bottom. The rising gas pulls a plume of warmer water up from deeper in the lake that keeps the hole open. The gas comes from decomposition of vegetable matter on the lake bottom. They are almost always in a limited area. Once the area of concern is identified, it is easy to check to see if they will be a problem. Most (but not all) the ones I have encountered were associated with a stream that empties into the lake nearby.

They tend to be a problem in the early part of the season. By mid-season the cold weather often overpowers the ability of the gas to keep the hole open. Late in the season or during mid-winter thaws they are often the first places to open up. Last spring on Lake Dunmore, Dave Terwilliger sailed up to the starting line, stepped out of his boat and fell through a gas hole to his shoulders! They certainly were not easy to see. We had not encountered them in this area in the early winter when we usually sail there. Based on this, they may be more numerous in the spring than at first ice.

Hud Brush, who has several gas holes in front of his camp says they will freeze solid it you poke a hole in the skinned over holes to let the gas out. It this is done with the help of some matches the project can be quite entertaining. Be Careful!

Characteristics of Gas Holes

1. They have a stream of gas bubbles in their center. The bubble stream may be intermittent.
2. They are typically round with a dimension of 1 to 4 feet although they often join together to form larger, irregular holes.
3. They often skin over at night making them treacherous.
4. They are almost always in the same area or even the same exact spot from year to year. (When you are sailing on a new lake, ask the locals about the ice. On Lake Honeys it turned out that local fishermen had told some of the iceboaters about the gas holes there.)
5. If the ice is clear it will often have large white gas bubbles in it.
6. They are often (but not always) associated with stream or river entrance areas. They may be a considerable distance from the actual stream entrance.
7. They are more of a problem in the early and late season than in the cold part of the winter. In the spring they may be an especially white spot or lump on the ice. They are hard to recognize with old snow drifts and other features in spring ice.
8. They often skin over at night and reopen during the day.

The next article will cover holes that are typical of midwinter ice. It you have anticdotes, other perspectives or additional thoughts on this subject, please give me a call or drop me a line.