It's Official: Lake Champlain Froze Over Friday

Satellite view of Lake Champlain taken Friday afternoon showing it
is completely iced over. Open water would be seen as areas of
bluish-black. Dark areas on the surrounding landscape in this
satellite are mostly areas of conifer trees.

The National Weather Service in South Burlington made it official yesterday, so I might as well today:

Lake Champlain froze over.

For the first time since February, 2015, ice entirely covered the lake Friday.

Satellite imagery taken on a crystal clear, cloudless afternoon Friday showed no signs of open water on the lake. Since late February when most of the lake froze there had still been small open spots in the ice well off the coast of Burlington.

As far as freeze overs go, this one is pretty late. Usually, if the lake does freeze entirely, it happens in late January or February.   In somewhat unreliable records dating back to 1816, I could only find four years in which the lake froze over as late or later than it did Friday.

By this time in March, the sun angle is higher, and the dark water near the edge of the ice does a better job of absorbing the heat. That melts the ice from the edges of the water, keeping open spots.

Plus the nights are a little shorter, so there's not as much time for ice to re-freeze after the sun goes down.

But we had three days of mid-January chill this past week. Thursday night and the hours before dawn Friday offered the perfect conditions for freezing over any open spots in the lake: Winds were near calm, and the temperature fell to near zero.

Since it's so late in the winter, don't count on the lake staying completely frozen for long. For all I know as I write this at 2 p.m. Saturday afternoon, open spots might have re-formed. After all, the sun is blazing down nicely, and temperatures even in the shade are near or above freezing.

On Sunday, strong winds will probably shift ice, allowing for the possibility of more open water. If that and above freezing readings Sunday and Monday afternoon don't open up a few spots, expected temperatures in the 50s late next week probably will.

All this is to say don't count on the Lake Champlain ice being safe everywhere. Don't follow the rather tongue-in-cheek suggestion of television station WCVB in Boston to drive across the Lake Champlain. You might plunge through a pressure crack or weak spot with your vehicle.

You'll see a lot of vehicles and people on the thicker ice over bays and such ice as people ice fish or skate.   That's probably safe in the short term, but will get more and more unsafe as the month goes on.

Lake Champlain does not completely freeze over as much as it once did. However, the data is skewed because there weren't satellites to detect open spots years ago. So before the satellite era, the lake might have been deemed frozen over from viewers on shore, but there still might have been spots of open waters.

Still, I suspect climate change is taking somewhat of a toll on lake ice, because Vermont winters are demonstratively warmer than they were decades ago.

In the 19 years since 2000, the lake has frozen over only eight times. Before, say, 1970, back to 1816, when people started  really monitoring the lake, it froze over most years. Again, though, some of those years might have had small spots of open water people missed.

It's not just Lake Champlain that has a lot of ice this year. As of Friday, the Great Lakes were about 80 percent ice covered. That's only the ninth time in the past 47 years there was that much ice on those lakes. Like on Lake Champlain, the Great Lakes probably have the peak amount of ice they're going to get this winter. .