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<br />Ramsey County | Multi-Jurisdiction Hazard Mitigation Plan 80 <br /> <br />3.12 Tornado and Windstorm <br />3.12.1 PROFILE <br />High winds can be produced during severe thunderstorms, with other strong weather systems, or by <br />flow down a mountain. There are several types of damaging winds possible in Minnesota: <br />• Straight-line winds describe any thunderstorm wind that is not associated with rotation and is <br />used mainly to differentiate from tornadic winds. <br /> A downdraft is a small-scale column of air that rapidly sinks toward the ground. <br /> A downburst is the general term used to broadly describe macro and microbursts. <br />Downburst is the general term for all localized strong wind events that are caused by a <br />strong downdraft within a thunderstorm, while microburst simply refers to an especially <br />small downburst that is less than 4 km across. <br /> A gust front is the leading edge of rain-cooled air that clashes with warmer thunderstorm <br />inflow. Gust fronts are characterized by a wind shift, temperature drop, and gusty winds out <br />ahead of a thunderstorm. Sometimes the winds push up air above them, forming a shelf <br />cloud or detached roll cloud. <br /> A derecho is a widespread, long-lived windstorm that is associated with a band of rapidly <br />moving showers or thunderstorms. A typical derecho consists of numerous microbursts, <br />downbursts, and downburst clusters. By definition, if the wind damage swath extends more <br />than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) <br />or greater along most of its length, then the event may be classified as a derecho. <br /> A haboob is a wall of dust that is pushed out along the ground from a thunderstorm <br />downdraft at high speeds. <br />• Tornadoes are defined as violently rotating columns of air extending from thunderstorms to the <br />ground, with wind speeds between 40-300 mph. They develop under 3 scenarios: (1) along a <br />squall line; (2) in connection with thunderstorm squall lines during hot, humid weather; and (3) <br />in the outer portion of a tropical cyclone. Funnel clouds are rotating columns of air not in <br />contact with the ground; however, the column of air can reach the ground very quickly and <br />become a tornado. <br />3.12.2 LOCATION <br />All communities within Ramsey County are vulnerable to windstorms and tornadoes. Minnesota lies <br />along the northern border of Tornado Alley, a loosely defined area first described in 1952 in the central <br />United States where tornadoes are more likely to occur than in other parts of the continent. <br />Interestingly, tornado activity has been shifting away from the Great Plains and toward the Midwestern <br />and Southeast U.S. according to a report published in the April 2024 issue of the Journal of Applied <br />Meteorology and Climatology.