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Don't hate the snow too much

Despite the smattering of snow earlier this week, it appears winter is finally losing its grip on the north. Snow is melting fast and as long as overnight temperatures stay above zero, it should be gone relatively quickly.
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Despite the smattering of snow earlier this week, it appears winter is finally losing its grip on the north.

Snow is melting fast and as long as overnight temperatures stay above zero, it should be gone relatively quickly. But a rapid melt is not necessarily a good thing from an ecological perspective. Snow is a critical component in the hydrological cycle.

We all learned about the water cycle in school. We are taught ocean water evaporates into the air to form clouds, which move over land where they come down as rain, and the rainwater forms lakes and streams which feed rivers returning the water to the oceans.

The cycle is actually way more complex. For example, some of the rain falls directly back into the ocean. Water in the atmosphere can remain as humidity and not nucleate into clouds. Fog and mist can shift water into trees and forests without forming rain. Plants take up water and release it through their leaves returning some rainwater directly to the atmosphere. And so on.

Indeed, there are components to the cycle we are still trying to understand. For example, a recent article in Nature Geoscience presented research into the role of low-lying clouds and their cooling effect on coastal regions. The research examined the effects of carbon dioxide concentration on the formation of these clouds and showed increasing concentrations would suppress cloud formation leading to elevated temperatures. This is another driver which hadn't been taken into account previously, a feedback loop accelerating warming.

There are parts of the hydrological cycle for which we have a good understanding. Consider the simplistic notion of rain flowing back into the oceans. It will eventually. That is, if you were to follow a single molecule of water for the next 10,000 years, there is a high likelihood it would spend some time as part of one of the oceans.

But it could also be trapped in a glacier for an extended period of time. Indeed, 10,000 years in a glacier isn't really a very long time. An international team of scientists is about to drill the deepest - and oldest - ice core yet from Antarctica. The core will extend 2.75 kilometres into the ice and it is estimated the bottom will be 1.5 million years old. Trapped inside every centimeter of the core will be a record of the Earth's meteorological history - water from hundreds of thousands of years ago.

The scientists will be able to decipher temperature and atmospheric conditions through a combination of isotopic analysis and direct gas sampling. Their work will extend our understanding of Earth's climate.

A more immediate concern is the delayed release of water vapour from snow. B.C. is home to an impressive amount of the world's freshwater (approximately four per cent). A significant portion is tied up every year in the snowfall. The depth of the snowpack determines how much will end up flowing through the landscape and eventually through the streams and rivers.

Despite the amount of snow still around town, the snowpack in the central interior is only at "normal levels" (somewhere between 90 and 110 per cent of yearly averages). Further north, in the Liard region, it is only at 76 per cent. In the Stikine and Skeena-Nass the snow loads are at 59 and 82 per cent, respectively. Similar low values are seen all along the coast and in the south Thompson and Kootenays.

What this means is we are likely in for another hot, dry summer replete with forest fires.

Furthermore, the rate of the melt in some of the alpine regions has been more rapid than usual resulting in water coursing over the landscape and not replenishing the water table. This will exacerbate the dry conditions leading to a higher likelihood of fire.

The next hundred years will see a significant shift in the flow and abundance of water through the hydrological cycle in British Columbia.

While we will likely maintain a large supply of freshwater, the landscape will dry out and forest fires will continue to be a summer event.