Great Lakes ice cover very low: What it means for summer
Tuesday, January 31, 2017, 5:07 PM - Ice cover on the Great Lakes is at a near-record low, thanks to the January thaw, but watch out for what happens to the lakes over the next week!
Back in November, the Great Lakes were extremely warm.
This was the warmest the lakes had been in 16 years, and it has contributed to some of the lowest lake ice coverage on record for this winter season.
As of January 30, lake ice was only slightly below where it was just one year ago, but less than a third of what was on the water back in 2015.
Also, for the week ending January 29, 2017, the Canadian Ice Service is showing that lake ice is at its fourth lowest level since 1981, after 2006, 2002 and 1995.
With the chilly air temperatures through December and, at times, in January, this has meant significant lake effect snow for southern and southwestern Ontario.
Based on what the forecast looks like, however, lake ice is set to grow, possibly to its largest extent so far this season, due to the temperature plunge that's setting up for our near future.
With lake temperatures only running about degree or so above normal for this time of year, it isn't going to take much to get the water to freeze.
"It won't be thick ice," says Weather Network meteorologist Matt Grinter, and it may not last long, but this will likely cause a significant growth in exactly how much of the lakes is seeing ice coverage over the next week.
Eyes ahead to Summer 2017
Even with all of the open water so far this season, the Great Lakes have managed to avoid having the lowest maximum extent on record. According to NOAA's Great Lakes Environmental Research Laboratory, they reached 13.5 per cent coverage on Jan 16, 2017, compared to a seasonal max of 11.9 per cent in 2002 and 12.9 per cent in 2012.
Still, depending on what happens in February, the lakes may struggle to get out of the bottom five years in the record books.
Credit: NOAA GLERL
Looking ahead, towards summer, this could mean another year of low water levels across the Great Lakes, due to the effects of evaporation.
Evaporation from the lakes is driven by the difference in the temperatures of the water and the air. The higher the water temperature, compared to the air, the greater the amount of evaporation there will be from the lakes.
During a cold winter, with the lakes frozen over, this halts evaporation by putting a barrier of ice between the water and air. Lake effect snows are rare, at best, and even in spring and summer, after the lakes melt, the greater amount of ice results in lower water temperatures, which keeps evaporation to a minimum. Thus, it doesn't take much rainfall over the lakes to keep water levels higher.
During a warm winter, where the lakes are mostly ice-free, these warm lakes with less ice coverage directly result in more evaporation. This contributes to repeated lake effect snowfall events during the colder months, which are able to kick off simply by having the winds align properly over the lake surface. Later, as conditions warm during spring and into summer, the lake temperatures tend to stay a step ahead of the air temperatures, which results in stronger evaporation from water surfaces in the warmer months too.