Flathead Lake nearly achieves complete ice-over

American coots bobbed in what remained of open water earlier this week on Flathead Lake and eagles perched nearby in a waterfowl mood.

Jim Craft, a research scientist at the Flathead Lake Biological Station at Yellow Bay, estimated that roughly 95 percent of Flathead Lake was frozen over on Tuesday.

“All I saw were a couple of open channels,” he said.

Craft said the last time the lake was similarly frozen was probably 26 years ago, in March 1993.

Flathead Lake’s longest period in recent history of complete ice cover was between December 1985 and March 1986, according to Flathead Lake Biological Station records. The lake was frozen for 79 days.

This week’s icing of Flathead Lake followed a stretch of sub-zero cold paired with comparatively little wind.

Craft said wind that kicked up Thursday began to break up the ice.

He said Flathead Lake’s size, depth and currents typically preclude the lake from icing over completely. Flathead Lake is about 192 square miles and reaches depths of more than 300 feet.

Glacier National Park’s Lake McDonald also reached a nearly complete freeze over during the recent stretch of bitter cold.

Now, as the spring equinox approaches, Flathead Lake is beginning to wake, said Craft, whose research focus is “limnology” — the study of inland waters.

Reporter Duncan Adams may be reached at dadams@dailyinterlake.com or 758-4407.