The Lake of the Ozarks is in transition.
Just days ago, open water could be seen for miles, often reflecting the sun in awesome sunsets and sunrises. Even after a snowfall, the contrast between the dark blue water was stark against the bright snow.
That changed this week as the lake is beginning to freeze over almost entirely in the wake of bitterly cold temperatures.
"The Main Channel is freezing over now," noted Warren Witt, director of hydro operations at the Bagnell Plant. "It's even freezing in front of the dam, which is the lake's deepest part. We haven't seen that for a long time."
Most of the coves are now frozen over, and the Main Channel near the Community Bridge is succumbing to the bitterly cold temperatures. The lake area experienced below zero weather a few weeks ago, setting the stage for the latest round of frigid weather. The temperature has been below freezing ― most days barely into the teens with nights in the single digits ― since last weekend.
There is no clear data, Witt says, but based on his recollection this is the most ice the lake has seen since around 1983. The lake reportedly froze completely over in 1977, thick enough to allow vehicles and some ice fishing.
As far as operation of the dam itself, the ice has had no impact. The equipment that pulls water through the dam is 40 feet below the surface, so intakes are not affected.
"As far as physical operation of the plant, there haven't been any issues," he said. "But the ice and cold weather impact how we approach operation of the dam, and what impact the demand for energy has on how we operate the dam."
The unusually cold weather has increased the demand for electricity, so the Bagnell Plant has been called on for additional generation. Even the Osage River below the dam has seen more ice than usual, and damage to docks downstream can result when the river rises during periods of increased generation.
"The demand for power is very high right now, so we have to balance all of that and still generate to meet the demand," Witt explained.
Jeff Green, Ameren shoreline management supervisor, Ameren has had some reports of damage to docks, "which is common this time of year, especially when we have high winds. The lake goes down and loosens cables, then the wind picks up and breaks the loosened cables."
Ice around docks with falling or rising lake levels can cause significant damage as well, he explained. De-icers should be kept running to keep docks from freezing in. He recommends periodic inspection of docks, and second homeowners should have a neighbor or dock builder periodically check their dock.
Page 2 of 2 - "Ice on the lake is dangerous in other ways," he noted. "Do not walk on lake or shoreline ice. With falling lake levels it can be hard to get back to dry land if you fall through the ice or fall on shoreline ice."
The Federal Energy Regulatory Commission (FERC) mandates a Guide Curve, which is followed by Bagnell Plant officials in regulating the lake level. Witt said the lake level is typically around 654 (feet above sea level) this time of year and stays there for about six weeks before returning to in-season levels. The additional generation for electric demand brought lake to the 654 about a week ahead of schedule.
"Generation is how we drop the lake level," he explained. "When and how much we drop the lake is based on energy markets and demand. The demand has been very high so we have to generate to meet that demand and follow the Guide Curve at the same time."
Last winter, the lake was in the middle of a severe drought and Ameren officials received special permission from FERC to leave the lake higher than the Guide Curve model in case the spring rains were not enough to raise the lake level before Memorial Day.
"Through January and February, we hardly had any water available for generation," Witt said.
Daytime temperatures are forecast to remain at or below freezing well into next week, with overnight lows in the teens or lower. The majesty of a lake covered with ice should remain for quite some time.