AUSTIN (KXAN) -- The term "blue norther" is a phrase familiar mainly to native Texans. It refers to a strong cold front that rapidly moves through Texas, causing a sharp drop in temperatures and often bringing unsettled weather ahead of the front. Like a typical cold front, winds shift behind it (usually out of the north/northwest) and can be gusty at times. The exact origin of the term is unclear, but several folk theories exist. Some believe it comes from the dark blue hue of the clouds ahead of the front, typically when the weather is unsettled. Others think the name "blue norther" comes from the clear, blue sky that appears after the front passes. These cold fronts typically occur during the fall months and can sometimes bring severe weather. When a strong cold front drops temperatures, it’s important to wear multiple layers, as the temperature can plummet rapidly by as much as 20 to 30°F in just a few hours. Over a century ago, the central United States experienced one of the most dramatic blue northers, called the Great Blue Norther of Nov. 11, 1911.