Watch Great Lakes ice cover TRIPLE from latest Arctic blast
Tuesday, February 13, 2018, 2:37 PM - Great Lakes ice cover saw a rapid surge in growth over the weekend, as yet another blast of Arctic cold caused it to reach its largest extent in the past three years, far exceeding the forecast seasonal maximum issued by NOAA, back in December.
It has been a very snowy winter for southern Ontario, thanks, in part, to the general lack of ice cover on the Great Lakes. As the lakes struggled to cool down through fall and the start of winter, after a spike in lake temperatures, it set up the perfect conditions for lake effect snow squalls, as the weather turned colder. Repeated blasts of frigid Arctic air sweeping down over the region contributed to this, as very cold air blowing over warm lake water is the ideal combination for squalls, which can produce sudden white-outs that spark commuter chaos, and can quickly dump significant amounts of snow along their path.
Each passing of one of those cold lobes of the polar vortex took its toll on lake temperatures, though. As a result, in late December and early January, we saw Lake Erie almost completely ice over. Lake Erie, however, is the shallowest of the five Great Lakes, and thus the quickest to give up its stored heat.
Overall, though, even as Lake Erie was nearly completely frozen over, ice coverage across all of the Great Lakes still remained low at the beginning of 2018, reaching just shy of 30 per cent at the time, and then only getting up to around 35 per cent by the middle of January. Since then, ice growth had largely stalled on the lakes.
Back in December, NOAA's lake ice coverage forecast called for a seasonal maximum of around 26 per cent. In contrast, the winter forecast from The Weather Network was calling for not only more snow this winter for southern Ontario, but also more ice growth on the lakes, with the expectation that it would at least exceed the long term average of 55 per cent. At least in December and January, it appeared as though NOAA's forecast was going to be the closer of the two.
Still, with even more frigid Arctic air sweeping through the region, each snow squall generated, each clear, chilly night, and each cold, cloudy day, has sapped a little more heat from the lake waters. Now, after this latest blast of cold, we've seen the result.
Great Lakes ice cover, which started out the month of February at only around 22 per cent, more than tripled over the next 10 days, reaching 69.1 per cent on Sunday, February 11, mainly due to Lake Erie's near total coverage, and surges of ice growth on Lakes Superior and Huron.
Great Lakes ice cover, February 11, 2018. Credit: Great Lakes Environmental Research Laboratory/NWS/NOAA
Watch, again, as ice expands across the Great Lakes so far this winter.
This is the greatest lake ice extent we've seen in the past three years. In 2016, maximum ice coverage reached only 33 per cent, in mid-Feburary and in 2017, it was just shy of 20 per cent, in mid-March.
Looking at Sunday's ice coverage compared to the same day in 2016 and 2017, the difference is remarkable.
Great Lakes ice cover for February 11, in 2016, 2017 and 2018. Data from GLERL/NOAA. Graph by Scott Sutherland
Ice cover in the two years prior to that - 2014 and 2015 - was significantly higher, of course. On February 11, 2014, total Great Lakes ice cover was at 88.4 per cent, on its way up to a 92.5 per cent maximum for the season. The same day in 2015, total ice cover was at 60.5 per cent, on its way up to a maximum of 88.8 per cent for the season.
Great Lakes ice coverage seasonal maximums, 1973-2017. Credit: GLERL/NOAA
Based on the forecast for the Great Lakes area in the days ahead, ice coverage is expected to retreat again, so we could be looking at Winter 2017-2018's seasonal maximum, right now.
Stay tuned, though. Winter certainly isn't over yet, and depending on how much the lake ice retreats during the latter half of February, if we see another surge of ice growth, due to another potential pattern swtich in early March, it could even top what we've already seen on the lakes so far this season.