Turns out the cold weather gripping much of the country is more than just freezing the body of anyone outside it in- it's also causing some refinery problems in the hardest hit areas.

This is something we've previously talked about, as well. Extreme weather can impact more than you may realize, and just in the last two days, is resulting in some problems, especially at refineries in the Midwest.

Several key units at Marathon's refinery in Detroit were shut down last night, and less activity at the plant has been been noticed, according to sources. This is significant because all of the units affected are vital to production of finished fuels, such as gasoline.

ExxonMobil's refinery and Citgo's refinery, both near Chicago, were also suffering from flaring events, which generally indicate a process upset or malfunction, a direct result of temperatures that approached -20F in the area, according to a filing with officials.

BP and Husky's joint refinery in Toledo, Ohio, also saw a unit shut earlier this week. Production of gasoline likely took a hit as the units involved in that shut down are also both are vital to production of gasoline.

Spot gasoline prices traded higher in the Great Lakes as a result of the many issues that developed because the cold weather. While these issues are temporary, shut downs or process upsets can have a very swift impact on retail gasoline prices, and motorists in these areas may see short term price adjustments as a result of the temporary loss of some gasoline production.

At this writing, it is unknown when the units mentioned will be completely back online, but in typical situations, it may be a matter of several days after the weather event has passed before the refineries are back at previous levels.