Over the course of several days during the last week of February, homes located along the eastern edge of Lake Erie in Hamburg, New York, were quickly transformed into ice-covered igloos. While mesmerizing images like the one above depict the dramatic scene that unfolded along the shore, the situation was nearly disastrous for residents of the area, darkening their homes and forcing them to navigate ice nearly everywhere they went. But, how did these ice structures form and why don’t we see this type of phenomenon happen every winter? Let’s investigate this particular event.
First, let's consider the geographic location of Hamburg. It is a small town that sits approximately 20 minutes south of Buffalo and borders the eastern edge of Lake Erie, a 255-mile long lake that stretches between Michigan and New York. Most winters, a large portion of the lake freezes over by the end of February. In fact, the Great Lakes Environmental Research Laboratory (GLERL) reports that over the last 40 years, ice-coverage during the last week of February has averaged 60%, with 92% coverage just last year in 2019. On February 29th, 2020, Lake Erie was merely 10% covered with ice. It is important to note that water changes temperature more gradually than air, this is why lakes do not instantly ice-over as soon as air temperatures drop below freezing, but instead slowly freeze as the air temperature remains below freezing for an extended period of time. Therefore when combined with strong winds directed over the lake and out of the west, a lack of significant ice-coverage can allow for the formation of very large waves along the shoreline. When these waves crash onto land and into surfaces such as houses and walkways with temperatures well below the freezing mark, the liquid molecules instantly freeze and, over time, can create the captivating yet dangerous scenic picture above.
These ice structures occur so rarely because they require this perfect combination of weather conditions. A majority of Lake Erie must remain liquid water well into the winter months and requires a storm that contributes high winds from just the right direction to cause high waves that crash into surfaces cold enough for instantaneous freezing to occur. While coinciding only rarely, this particular meteorological setup helped create some of the most fascinating and unique homes in America for a few days at the end of February along the eastern shoreline of Lake Erie.
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©2020 Weather Forecaster Dennis Weaver
Winter of 2019-2020 was a very mild winter when compared to the blasts of Arctic air we saw in January 2014. The reason for this mild winter can be attributed to the polar vortex. One question you may be asking yourself is what exactly is the polar vortex and how does it affect whether we have a mild winter or not? The term polar vortex refers to a cone of low pressure that sits directly over the poles. The polar vortex is made up of a fast-flowing stream of air that envelops the North Pole.
The polar vortex is strongest in the winter due to the increased temperature gradient between the mid-latitudes and the poles that, in turn, strengthens the jet stream. This takes place in the stratospheric layer which is typically around 6 to 30 miles above ground. When the polar vortex is the strongest, all the cold Arctic air is trapped at the poles, but when it starts to weaken, Arctic air will plunge into North America or Europe. For much of the winter of 2019-2020, the polar vortex has remained strong which has kept the CONUS warmer than average.
(Image Credit: NOAA)
The image above shows that during a stable polar vortex like this current Winter all the cold air is contained to the north; however, when the polar vortex starts to collapse cold air will move south while warm air moves to the north causing a wavy polar vortex to sweep across North America or Europe. The wavy polar vortex will produce blasts of cold air as the pattern progresses across the Northern Hemisphere. This trapping of Arctic air in the polar latitudes has allowed record heat to dominate over colder temperatures for the last part of 2019 and first part of 2020.
According to the Weather Channel, the polar vortex should remain strong at least through March. This means the CONUS can expect above average temperatures this spring.
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©2020 Weather Forecaster Hannah Peters