Historical Electricity Price Trend
The below powerpoint slides were provided by Constellation Energy. They show historical pricing for the Polar Vortex weather trend in 2014 for First Energy and AEP territories in Ohio.
The orange highlighted area in the left line graph is expanded in the graph to the right. You can see that electricity pricing increased after the Polar Vortex, however has not come back down to the level it was in January 2014.