Read this: Because of Oklahoma's position between zones of differing prevailing temperature and winds, weather patterns within the state can vary widely over relatively short distances and can change drastically in a short time. As an example, on November 11, 1911, the temperature at Oklahoma City reached 83 °F (28 °C) in the afternoon (the record high for that date), then an Arctic cold front of unprecedented intensity slammed across the state, causing the temperature to crash 66 degrees, down to 17 °F (−8 °C) at midnight (the record low for that date); thus, both the record high and record low for November 11 were set on the same date. This type of phenomenon is also responsible for many of the tornadoes in the area, such as the 1912 Oklahoma tornado outbreak, when a warm front traveled along a stalled cold front, resulting in an average of about one tornado per hour over the course of a day.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What caused Oklahoma's temperature to plummet 66 degrees on Nov 11, 1911?
an Arctic cold front