Rochester, MN (KROC AM News) - The Rochester area may be in its second straight week of below freezing temperatures but RPU has issued a warning about ice conditions at Lake Zumbro.

RPU says it continues to draw down the lake to its normal winter level, a process that it taking longer than normal this year due to a number of factors.

RPU says as a result, there is a danger of unstable ice covering the lake. RPU says this threat will continue until the drawdown is complete.

RPU says visible ice on the lake - especially close to shore -  may be very unstable because it hasn’t had time to set at the winter pool level.

According to the Minnesota Department of Natural Resources, ice is not safe to walk on until it is 4 inches in thickness.

RPU has these tips for lake ice safety:

Be extremely careful during winter activities that involve Lake Zumbro such as ice fishing, snowmobiling or just walking out on the frozen lake.

Watch the weather and river flow conditions.

Ice thickness and condition can vary greatly.

Look out for ice heaves and exposed logs and snags.

Be cautious in the vicinity of the power dam. De-icing equipment has been installed along the upstream face of the dam resulting in open water and/or thin ice. Do not proceed past the warning signs and buoys.