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Ramsey County Multi-Hazard Mitigation Plan, 2018 Page | 42 keep their local governments aware of the hazards that face their communities and how to mitigate those hazards through planning and project implementation. Each jurisdiction has identified mitigation strategies they will seek to implement in their communities (see Appendix G: Mitigation Actions by Jurisdiction). Jurisdictions will include considerations for hazard mitigation in relation to future development when updating local comprehensive plans or other plans that may influence development. Section 6 of this plan further outlines the process by which Ramsey County will address the maintenance of this plan, including monitoring, evaluation, and update of the plan, as well as implementation and continued public involvement. 4.4 Hazard Profiles As part of the risk assessment, each natural hazard that poses risk to the county was independently reviewed for its past hazard history, relationship to climate change, and jurisdictional vulnerability to future events. A capabilities assessment was also conducted to review the plans and programs that are in place or that are lacking (program gaps or deficiencies) for the implementation of mitigation efforts. 4.4.1 Tornadoes Tornadoes are defined as violently-rotating columns of air extending from thunderstorms to the ground, with wind speeds between 40-300 mph. They develop under 3 scenarios: (1) along a squall line; (2) in connection with thunderstorm squall lines during hot, humid weather; and (3) in the outer portion of a tropical cyclone. Funnel clouds are rotating columns of air not in contact with the ground; however, the column of air can reach the ground very quickly and become a tornado. Since 2007, tornado strength in the United States is ranked based on the Enhanced Fujita scale (EF scale), replacing the Fujita scale introduced in 1971. The EF scale uses similar principles to the Fujita scale, with 6 categories from 0-5, based on wind estimates and damage caused by the tornado. The EF Scale is used extensively by the NWS in investigating tornadoes (all tornadoes are now assigned an EF Scale number), and by engineers in correlating damage to buildings and techniques with different wind speeds caused by tornadoes. To see a comparative table of F and EF scales, see http://www.spc.noaa.gov/faq/tornado/ef-scale.html. In Minnesota, the peak months of tornado occurrence are June and July. The typical time of day for tornadoes in Minnesota ranges between 4:00 p.m. and 7:00 p.m. Most of these are minor tornadoes, with wind speeds under 125 miles per hour. A typical Minnesota tornado lasts approximately 10 minutes, has a path length of 5 to 6 miles, is nearly as wide as a football field, has a forward speed of about 35 miles an hour, and affects less than 0.1% of the county warned. Tornado History in Ramsey County According to the NCEI, 7 tornadoes were reported in Ramsey County between 1950 and April of 2018, causing one death, 168 injuries, and $225,770,000 dollars in reported property damage. Tornado classification ranged from F0/EF0 to F4 on the EF/F Scale. The most recent tornado in Ramsey County occurred on July 17, 2015, when an EF-0 tornado touched down in the northwest portion of North Oaks, near Charley Lake. The tornado moved to the southern side of Deep Lake, where the highest numbers of toppled and snapped trees occurred. Some trees fell on houses, vehicles, and other structures, and the NCEI reported $500,000 in property damage.