PIERRE, S.D.(WNAX)- The South Dakota Public Utilities Commission put out a notice warning consumers of possible spikes in natural gas prices.

Commission Chairman Chris Nelson says prices have been sharply up and down.

Nelson says they put the notice out to give people time to prepare.

Nelson says utilities can automatically pass through the cost of their energy supplies.

Nelson says most utilities have assured them there will be an adequate supply of natural gas through the winter.