The date for the latest closing of Otsego Lake is rapidly approaching and the water in much of the lake remains open.

Dr. Williard Harman, director of the Biological Field Station on the shore of the lake said Tuesday that given the weather forecast, it is unlikely the lake will close - or cover over with ice - by February 25. That is the latest closing date for the lake according to records that go back into the 1840s' and was set in consecutive winters during 1931-32 and 1932-33.

"We're nearing that record and I don't think it will freeze. We're into a whole new ballgame," Harman said.

If the lake does not close, it will be a first for the more than 160 years records have been kept. A few years ago, former Cooperstown mayor and long-time weather observer Harold Hollis, declared the lake closed briefly one night — a call that was disputed by Harman. But even that winter, almost all the lake was covered with a thick layer of ice.

Matt Albright, Harman's assistant at the field station, said they have been receiving many phone calls from people interested in what's going on with the lake. "We must be getting two or three a day," he said.

Normally, Harman said, we have cold air trying to freeze a warm lake. Now we have a cold lake that wants to freeze, but doesn't have the frigid air required to form the ice.

"We need a couple of calm days in the mid 20s," he said. "The lake would love to freeze. If it was in the mid-20s for 48 hours, I think it would close up."

The problem is, the weather forecast doesn't call for those kinds of temperatures.

"Last night it closed up a lot," he said, explaining that a thin, transparent layer of ice had covered the lake up to about Sam Smith's Boatyard from the south and came down from the north end to the vicinity of Clark Point.

"It was making ice fast. But with the sun and temperatures in the low 40s there's no way the ice is going to stay," he said.

Harman illustrated how fragile the transparent skin of ice is just off shore from the Biological Field Station by rocking the floating dock to send a series of waves in the direction of the ice. As the waves reached the ice, the rolling water lifted the sheet and cracked it repeatedly as it moved outward further from the dock.

The water temperature, Harman said scientifically, is only a degree or two above freezing - all it needs is enough calories taken out to change state. Those calories - or heat - can be removed by exposing the water to air whose temperature is in the 20s.

Before the lake can freeze, the water must first turn over. As lake water cools in the fall, it becomes denser until it is a few degrees above freezing when it reaches its maximum density. It then sinks to the bottom displacing warmer, less dense water which rises to the surface. The circulation process continues until the whole lake has reached that temperature and density. The circulation of the water is vital to the cold water fishery in the lake because it helps to re-oxygenate the deep water.

When the water in the lake has cooled and turned over as it is now, it is only waiting for the cold air temperatures to freeze. The arrival of cold air chills the surface water further causing it to become less dense and float on top of the denser, slightly warmer water just below. If the air temperature remains cold enough the lake freezes over.

This winter's open water is be driven by a warmer than normal winter. Last month National Weather Service observers at the New York State Historical Association next door to the Biological Field Station recorded higher than normal temperatures 25 of 31 days. The mean, or average temperature for the month was 28.9 degrees - more than eight degrees higher than the norm and the 10th highest mean ever recorded for January. It also set the tenth highest mark for average monthly maximum temperature at 36.6 degrees.

"We simply have not had the number of days of below freezing temperatures that we normally have," Harman said.

Whether open water all winter will create problems later on is unclear because researchers at the field station have no experience to go by. "It's hard to tell," Harman said, "The biggest implication may be that there are no ice fisherman taking out lake trout. That change will cascade all over the place."

Albright said ice fisherman would typically take hundreds of lake trout which may not sound like a lot, but given that only 5,000 are stocked in the lake each year and as many as half of them may be lost to mortality, it is a significant number.

The field station director was hesitant to predict that the lake would not close this winter. "I'm getting the feeling that may be the case. I've looked at long-term forecasts and don't see the cold weather," he said. "But I'm still conservative. It only takes a day or two, but chances are better than not that it will not freeze," he said.