Winter weather is upon us and Black Hills Energy is encouraging customers to be prepared for the extreme cold.

Black Hills Energy spokeswoman Sharon Fain says customers can make sure they're ready for a winter storm by keeping a stockpile of blankets as well as flashlights with fresh batteries on hand.

"We're also encouraging customers to consider an annual furnace inspection and tune-up to make sure their heating equipment is running efficiently and safely venting the carbon monoxide created in the combustion process," said Fain.

Signs of a potential carbon monoxide leak can include, but are not limited to, flu-like symptoms including a scratchy throat, runny nose, headache, drowsiness or nausea.

Other indicators could include frosted windows or a draft from the front of the furnace when it's not turned on.

"If any of our customers think there may be carbon monoxide in their home we encourage them to leave the premises immediately, dial 911 and contact our emergency service line at (800) 694-8989," said Fain.