The Nordic electricity spot power market (Nord Pool) is divided into several price areas. TheNO1area (southern Norway) is of particular interest. It is dominated by hydropower and has experienced large deviations from the system price. Using historical data (prices, reservoir levels and transmission congestion data), we statistically investigate the historical contributors to this price spread. The water reservoir level, followed by the Elspot capacity and Elspot net capacity utilization, are found to be the most important explanatory variables. As expected, lower capacity and more flow coincide with higher price spreads.