Have you ever wondered why some snow is light and fluffy, perfect for skiing, while other times it's a back-breaking, wet burden? The answer lies in a key meteorological concept: the snow ratio. This scientific principle explains the density of snowfall and has significant implications, especially when experts issue warnings about the health dangers of shovelling.
The Science Behind Snow Density
Meteorologist Kalin Mitchell provides crucial insight into this winter phenomenon. The snow ratio, often expressed as a ratio like 10:1 or 15:1, refers to the amount of liquid water equivalent in a given depth of snow. A common ratio is 10:1, meaning ten centimetres of snow would melt down to one centimetre of water.
However, this ratio is not constant. It fluctuates dramatically based on atmospheric conditions. When temperatures are very cold, the snow crystals form as tiny, intricate flakes with lots of air space between them. This results in a higher ratio, such as 15:1 or even 20:1, producing light, low-density snow that is easy to shovel but prone to drifting.
Conversely, when temperatures are closer to the freezing mark, the snow crystals become wetter and stick together, forming larger, heavier aggregates. This leads to a lower snow ratio, perhaps 5:1 or 8:1. This dense, wet snow contains much more water per shovelful, drastically increasing the physical strain of removal.
A Significant Health Hazard
The density of the snow is directly linked to a serious public health concern. Medical experts consistently warn about the cardiovascular risks associated with shovelling heavy, wet snow. The combination of intense isometric exercise, cold air constricting blood vessels, and the sheer weight of the snow can trigger heart attacks, particularly in individuals with underlying conditions.
The physical act of lifting heavy, water-laden snow places an immense strain on the heart and back. Each shovelful can weigh 15-20 pounds or more, and clearing a driveway can mean moving hundreds of pounds of snow in a short period. This is why public health advisories often follow major snowfalls that produce this dense type of precipitation.
Practical Implications for Canadians
Understanding snow ratios can help Canadians prepare better for winter storms. A forecast calling for 15 centimetres of light, fluffy snow (high ratio) presents a very different clearing challenge than 15 centimetres of heavy, wet snow (low ratio). The latter requires more caution, more frequent breaks, and perhaps consideration of a snow blower or hiring help for those at risk.
This scientific explanation underscores why weather reports are moving beyond just total accumulation. Providing context on the expected snow density and type is becoming increasingly important for public safety. Knowing whether to expect a light dusting or a heavy load allows people to plan their approach to snow clearing, potentially preventing medical emergencies.
As winter continues across Canada, paying attention to not just how much snow falls, but what kind of snow falls, is a critical piece of staying safe during the season's most challenging weather.
