The Exploits River froze early this year, and has created some problems for generating power at the Grand Falls Dam.
Approximately three weeks ago, the river froze, and around the same time an ice dam broke west of Grand Falls-Windsor, creating a clog near the dam.
Wilmore Eddy, Nalcor's manager of Exploits Generation, said this has seriously impacted their production.
"The challenge that we've had now is that we're trying to pull water through this ice cover, which is a severe restriction," he said.
"As a result of that, our generation output has been reduced for the last three weeks or so."
The dam typically generates up to 50 megawatts of power per day, but has only been producing around half that amount since the dam blocked up.
Eddy said the problems at the dam contributed to the power interruptions experience across the island throughout the week.
"When the grid was looking for as much power as it could get, the fact that we were 15 megawatts or so down below that at times didn't help the system," he said.
An excavator is being used to chip away at the mass of ice, and an engineer is set to arrive next week.
However, Eddy said without a warm spell, it could be March before the dam flows free again.