Backyard rink with snow walls
A snow bank can hold the flood water in place of boards. The two guides I opened for this give a height and one warning about the edges, but neither says how much snow that is. The calculator below does the volume. For the base itself and the thin first coat, see the page on a rink without a liner. For clearing snow once there is ice, see snow on a backyard rink.
Your snow
- Walls: 240 cu ft, 8.9 cu yd, 6.8 m³ along 120 ft of edge
- Base at 4 in: 267 cu ft, 9.9 cu yd, 7.6 m³
Open this rink in the calculator for the water.
How the numbers are made
This is my arithmetic. Walls: perimeter × bank height × bank width at the base, with every length in feet. Base: rink length × width × base depth. Cubic feet ÷ 27 gives cubic yards, and × 0.0283 gives cubic meters. The wall formula treats the bank as a straight-sided block, so a bank that tapers to a ridge holds less (a triangular profile is half of the block). The volumes are packed snow. Loose snow packs down, so you gather more than the figure shows, and I have no source for a ratio.
Worked example, 20 × 40 ft with a 12 in bank that is 24 in wide at the base (the width is my choice). The perimeter is 120 ft. Walls are 120 × 1 × 2 = 240 cu ft, or 8.9 cu yd. A 4 in base over the 800 sq ft is 267 cu ft, 9.9 cu yd. Together that is 18.8 cu yd of packed snow.
What the guides say
- Height. A Timbermart guide says to "build up a dense low snow bank around perimeter of rink at least 30 cm high to contain flood water." That is about 12 in, the height in the worked example.
- Base. The same guide lists "10-15 cm of snow" for the base and says to "pack down snow so it is hard and level." That is about 4 to 6 in. The City of Toronto guide on the no-liner page says 1 to 2 in. The sources disagree, so the table shows both.
- Edges. A 1983 Christian Science Monitor article says "it's important that the edges be watertight." It has you spray the edges with a hose to form a hard ice crust so the water does not leak out the sides.
Base depth, both ways
Packed snow for the base of your rink at the depths the sources give, using your rink size from above.
| Source | Depth | Packed snow |
|---|---|---|
| Toronto, low end | 1.0 in | 2.5 cu yd 1.9 m³ |
| Toronto, high end | 2.0 in | 4.9 cu yd 3.8 m³ |
| Timbermart, 10 cm | 3.9 in | 9.7 cu yd 7.4 m³ |
| Timbermart, 15 cm | 5.9 in | 14.6 cu yd 11.2 m³ |
Limits
- My suggestion: plan snow walls only for a place that stays below freezing for weeks. A warm spell softens a bank, and I found no source that gives a safe temperature.
- My suggestion: keep the site level. On a slope the low side needs a taller bank, which means more snow than the formula gives for an even height. See the slope guide.
- My suggestion: walk the edge on the first flood and patch any gap with packed snow before the water reaches it.
- If snow is scarce or the winter is mild, boards are the other way to hold the water.