In the last post we explored the fact that our last decade of winters have had some curious ups and downs. For the most part, the last few northern United States winters have been relatively mild, with 2012 giving us 80's in March and 60's in the dead of the season. Then we had an usual event for 2014, a brutal winter full of snow and ice and intense cold. Again, we explored the details, and found out that we have seen some deep chills even in our better winters. The truth is, they are part and parcel of life in the temperate zone, and we really need the cold to maintain our surroundings properly. Ice and snow have wonderful ways of keeping things moderated, without which life could be much worse for the planet. You see, we live on a round rock floating in an unforgiving interstellar space which is anything but moderate. Move our distance from our star even slightly, we have problems. Remove our protective layers of magnetic force and atmospheric gases, we have problems. Remove either the stable water thermodynamics of our oceans or the vast land spaces of our continents, we have problems. Remove the snow and ice...
Well do we have problems! First and foremost, the thing to keep in mind about ice is that it is cold. While this may seem to be rather obvious, think about what effect large masses of ice have on the waters and land which they freeze to a crisp. There is a reason why northern Ontario has the furthest southern tundra in the world: Hudson Bay. Here is a look at what that tundra, at the same latitude as Edinburgh, Scotland, looks like:
Yes, that amazing body of water is often frozen for the vast majority of the year. Unlike the rest of the world ocean, Hudson Bay is only lightly saline, a condition partially held in check by the ice it generates. The Bay is fed by a vast area of rivers and lakes draining into it, somewhere close to a third of all the water draining away in Canada and even a small amount of what escapes from the United States. These waters are thus able to more easily freeze in the winter, and when they melt when summer finally does reach her, the mighty Hudson is able to keep the salt water at bay (no pun intended). Like her perennial rival the Gulf of Mexico, the Hudson thus also influences the global circulation of water by adding fresher, colder water to the warm and salty mix elsewhere. This role ensures that heat is transferred out of the Bay, especially during those heated months. Masses of ice float around in the water even in August and September, and just like in the winter, they not only moderate the water temperature directly, but also reflect solar radiation back into space.
Needless to say, this has an effect on North American weather systems. Although the heat and humidity factory of the Gulf of Mexico usually kicks that tar out of the Bay during summer months (worthy of another post), the ice-influenced lower temperatures of the place tend to keep a nice forty to fifty degree dome of cold air that occasionally pushes southwards enough to keep our continent from baking in a total Gulf Sauna. You see, during the last ice age, the Bay actually reigned supreme in this regard; it kept on pumping out more and more ice as the climate cooled. Over thousands upon thousands of years, the ice made enough progress to spread far to the south, and summer no longer had the same effect that it does today. The ice started building up upon itself and, like a mountain, cooled off the rising air masses making their way over the higher elevations, at once cooling off the air and increasing the amount of precipitation to fall on it, which of course was snow.
This is the important part, now.
Snow and ice both reflect solar radiation, but snow has the added benefit of also insulating whatever it covers. Snow on top of a glacier thus blankets the ice and keeps the temperatures beneath relatively stable. On ground, this does the same thing, usually to the opposite effect of keeping the protected soil and associated life warmer than normal. Back in January when we hit that terrible low of -16F, my underlying brown Michigan clay stayed at about 28F under a foot and a half of snow, thus saving my outlandish experiments in botanical curiosity. Different experiments have revealed degrees of effectiveness in regards to insulation, but most findings report that every inch of snow gains us about 2 degrees F or so of protection. In our continent of playful temperature shifts, this is sometimes responsible for allowing things as tender as palms (mostly Sabal Minor) from growing naturally as far north as Oklahoma and North Carolina. Again, this is on the continent that also features Tundra as far south as Ontario. Its the gift of our winters that enables us to have productive farmland well into Alberta or apples as far south as Florida. We can have tundra in Ontario and freezes well into Mexico but we also don't have the brutal, crushing, seemingly eternal record low winters that Siberia gets. If you ever think that this cold has been nuts, take a look over at the Russian continental deathly cold factory known as Verkhoyansk. I dare you! They don't have the same powerful melting cycle-climate changing power that Hudson Bay presents, and they definitely get a lot less snow than we do; the atmosphere just does not have a decent enough source of moisture to draw off of.
You see, ice cools through multiple means, and snow blankets. Without them many species of plants would not flower, pollinators would be in an even worse shape than they already are, agriculture would suffer severely, and the deer would simply eat every seedling in sight that would otherwise be covered by snow. There are so many benefits to having snow come along with the cold, the most excitable one this year being a chance to finally punch the emerald ash borer in the face. Gradual melting of mountain packs in the Rockies and Sierras gives us the wonderful rivers that we have out west in the midst of some very hot and dry deserts. A sudden rush of melting and spring rains means that the moisture does not benefit from the time released majesty that snow would provide. I could go on, but that said, try chewing on this article by fellow blogger Johanna Dominquez:
The Benefits Of Snow!
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