Canada’s largest city – Toronto – is still recovering from a massive ice storm which blanketed the city and surrounding suburbs Dec. 21. Ice built up on power lines, causing the lines to collapse under the weight of the ice, and tossing over 250,000 area residents in the dark at the height of the storm.
A week earlier, weather forecasters were predicting a snow storm of mammoth proportions, with snow falls reaching 30cm (12 inches). As the storm approached from the south, air masses warmed, increasing temperatures, creating a freezing rain event, instead of a snow storm.
Despite the weather forecasters initial predictions, one thing remained – the enormous volume of the precipitation remained constant.
This past summer, much of Toronto was shut down because of another significant precipitation event, which flooded major roadways to the point that cars were actually floating down them as if being carried along a river. Basements filled with water, power systems failed, and Toronto’s subway system which ferries a million plus people per day to and from work was shut down.
More rain fell that one July 8 night than ever before – breaking the one-day rainfall record set in 1954 when Hurricane Hazel hit the city.
Both storms wreaked havoc on the liveability of these major urban areas, because of too much H20.
Water is the life giving liquid. Without water, there is no life as we know it – that’s why scientists look for water on Mars and other planets.
However, too much water can take away life too.
Two people died from carbon monoxide poisoning during the recent ice storm in Toronto, caused by having the gas generator too close to their home. They were using the generator to power their home, because of a blackout caused by the ice storm.
There were reports of some actually risking the same fate, by bringing their BBQs indoors to heat their home and cook on, during the city-wide power failures.
Water isn’t just the basic ingredient for life and death, but also the fuel which powers these super storms.
As water evaporates into our atmosphere, it cools and condenses to form clouds. As cool clouds float over warm water bodies – such as Lake Ontario south of Toronto – the warm water evaporates faster. It’s as if the cool cloud is like a sponge, sucking up the warm moisture from the lake below.
The cool cloud constantly grows as more warm moist air condenses. If enough of that warm moisture condenses – as in both the summer flood and the recent ice storm in Toronto – a supercell forms.
Supercells are among the most powerful storms on the planet. They can stretch hundreds of kilometers in all directions, and because of their enormous water volume, they are very slow moving.
It’s the one-two punch of these super storms, which makes them so dangerous. The first wallop occurs from the large volume of the rain, ice or snow they carry. The second wallop occurs in their slow speed, so all that precipitation falls in the same spot, instead of being dispersed over a wider area.
In the case of the ice storm, there is an additional layer of cold air in the atmosphere, precipitation begins as snow turns to rain as it falls through the warm air, and then those rain drops are supercooled as they fall through the second cold layer.
Supercooled water is really dangerous, as it remains liquid, even though it’s below the freezing point. The second the supercooled liquid hits something – a tree, a power line, a road, a sidewalk – it freezes onto that solid, forming an icy coating.
As oceans rise, we see an increase in supercells, and other severe storms – more moisture in our oceans eventually means more moisture evaporating into our atmosphere, which fuels these powerful storms which may flood or freeze us out of our homes, as we’ve seen in Toronto and around the world.