Friday Headlines, November 21, 2014
THE LATEST IN THE GEOSCIENCES
Lake Effect Snow
World’s Biggest Landslide
This week, the city of Buffalo, NY, as well as the Tug Hill Plateau (at the east end of Lake Ontario) got positively pummeled by lake effect snow.
Here we were, nice and cozy in Rochester (and by cozy, I mean freezing our hind ends off, but at least it wasn’t snowing hard!), while Buffalo, only an hour’s drive from here got buried in FEET of snow. YARDS. METERS!
How does this work? Why didn’t Rochester get (much) snow? Will it snow here?
Lake effect snow happens when cold, dry air passes over a warm body of water (just as the recent “polar vortex” just passed over the un-frozen and quite warm Lake Erie). The water evaporates and immediately freezes into snow. Lots and lots of snow.
For this storm, the winds were blowing primarily to the north east, bringing snow off of Lake Erie onto the Buffalo region. Later in the winter, the winds will shift to primarily from the northwest, which will bring lake effect snow off of Lake Ontario over the Rochester area.
Usually by the time Rochester starts seeing a lot of snow, Lake Erie will have frozen over, which shuts down the lake effect snow machine. Lake Ontario, however, seldom freezes over, so we can expect lake effect snow all the way until spring.
…Once the wind starts blowing the right way.
It was big. Like *really* big.
It happened some 20 million years ago (a little before any of us were around), and covered about 1,300 square miles, and moved around 55 miles.
Potentially the largest landslide that Earth has ever known. And it happened in Utah.
It started with volcanic eruptions, leaving a nice layer of igneous rocks on the surface. The volcanoes were (and still are) related to active tectonics in the Rocky Mountain area – caused by the subduction of the Farallon plate below North America. This is what originated the Rocky Mountains and most of the volcanoes associated with them.
Most of the Farallon Plate has been fully subducted beneath North America. Only a couple remnants remain, called the Juan de Fuca Plate to the north (under the Cascade Range), and the Cocos Plate to the south (under Mexico).
Earthquakes associated with fault motions as well as volcanic eruptions, coupled with steepening of slopes due to uplift and growing magma chambers, is what most likely triggered the massive landslide.
This is surely an event you could have watched (hopefully from a great distance), and would have been in the category of ‘you probably couldn’t escape.’