The Persistence of Snow

Back in the week before Christmas, I was lamenting how winter seems to be a fleeting bonus feature to the colder months of the year, at least across most of temperate North America.  Now the southern Great Lakes finds themselves covered in a nice foot tall blanket of snow that has thus far managed to survive nearly two weeks intact, with only two days managing to partially melt any of it.  During the initial snowfalls, we had lovely scenery: our majestic oaks, hickories, maples, ashes, and willows were gently draped with marshmallow puffs of powder.  The small amount of naturally occurring cedar or pine that we have here in southeastern Michigan (and of course all the cultivated masses of spruce) added a nice splash of green and "north" to a scene that was otherwise expected to be dull, muddy, and of limited color.  This transformation got me thinking about something my imagination has always been ready to venture into, yet not quite sure how to handle.

Just what was the last major glaciation like, and how was it even possible?

Many of our scientists tell us that the Laurentide Ice Sheet was over a mile tall and covered the continent from the far north all the way down to central Ohio.  These same people also tell us that a shift of only a few degrees in average global temperature could reproduce this, or worse, in the other direction, it could turn our little green and blue marble into something a bit more brown and toasty.  On the surface, it sounds pretty sketchy and dubious at best.  After all, Climate Change is but one of the many issues in our lives that has been bitten by the political vampire and turned into an ugly beast that ever polarizing sides want to keep fighting on.  That said, we do have quite a bit of evidence out there to show that we really did have an ice age within the last ten milennia, among the favorite of mine being the fact that Britain is rising in Scotland and sinking in southern England.  The same thing is happening here in North America, with the most apparent place of rebound being in extreme northern Ontario along the Hudson Bay lowlands.  That's right.  Apparently we had so much white stuff crushing down on the poor earth that it keeps springing back up to this present day.

Anyway, accepting for a minute that we did have an Ice Age (and yes, I am among those who say that we did have a "recent" one), well, how were things working out back then?

Things were working out very differently.

For starters, someone standing in what would become Columbus, Ohio, would not be staring at a huge wall of ice, but something more akin to a slope of, you guessed it, a glacier, that would gain elevation to the north.    There would still be seasons, and as is the case with the edge of most modern montane and polar glaciers, there would be a bit of melting going on during the warmer months, melt-water of which would find its way into the ancient versions of our modern rivers, such as the Mississippi.  At the end of its life, the Laurentide Ice Sheet would be fighting a losing battle during the summer, and the melting would produce massive channels to drain all that water back to the rising oceans, most notably in the Mississippi and Ottawa rivers and their ancient versions.  In some places, what melted would pool up.  We can thank this sort of deal for giving us the Great Lakes.  In the reverse scenario, we can probably figure that the ice sheet got its start the same way, but not melting as much during cooler summers so that winter replacement would gain the upper hand.  Basically, the war that has been forever going between the Gulf of Mexico and Hudson Bay started to turn in favor of the Bay, which kept on pushing out more ice and other white stuff further south than anywhere else in the northern hemisphere.  During the glory days for the northern team, the ice would have piled high enough to create a new climate on itself, cooled by its own elevation.

But enough about ice and giant rivers with massive rapids that would make Niagara Falls seem like a leaky faucet, what would become of all the wee critters and lovely trees?  Many of them would migrate south.

It's hard to imagine a world where one could catch Lake Trout (Salvelinus Namaycush) in Alabama or see spruce bogs along the Gulf coast, to say nothing of having a hard time finding a palm tree in Florida, but such things might have been the case.  We do know that some northeastern species of pine retreated as far south as Oaxaca down in central Mexico, relict species of which can still be found in such a place.  Today it can snow in the higher elevations around Mexico City, at least during the middle of winter around the turn of the year.  Back then, a white Christmas in the area now claimed by the city proper would not be out of the question.  Of course it would not stick around for very long, but back then the snowy winter scene I see outside would have had the upper hand much further south.