Resolution 7478 hazard mitigation

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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan Volume 2 — Hazard Inventory Other Notable or Recent Extreme Thunderstorm Wind Events o September 21, 2005 (Hennepin County) —Large, slow -moving supercell thunderstorms produced large hail, tornadoes, and extreme downburst winds in Anoka and northern Hennepin County, with wind gusts estimated up 100 mph in Brooklyn Center, where a man was killed by falling trees. o September 20, 2018 (southern Minnesota) —A line of fast-moving thunderstorms, like a serial derecho but not traveling far enough to qualify, produced nearly continuous and severe damage as tornadoes and straight-line winds ravaged communities in south- central and southeastern Minnesota, including Waseca, Owatonna, Faribault, Northfield, and Cannon Falls. National Weather Service surveys indicated straight-line winds exceed 100 mph. o July 19 (central Minnesota and July 20, 2019 (southern Minnesota) —An intense heat wave with Heat Index values to 115' F fueled a derecho that tracked 490 miles from central Minnesota into Michigan. The next day, as the heat dome settled southward, another derecho tracked 860 miles from western South Dakota, through southern Minnesota, Wisconsin, and northern lower Michigan, crossing the damage path of the previous day's extreme winds in Wisconsin. o August 10, 2020 (Iowa and Midwest) — One of the most extensive and destructive mainland storm events in US history, an extreme derecho tracked from the Iowa/Nebraska border to the Indiana/Ohio border, reaching maximum intensity in eastern Iowa, where winds gusted over 100 mph over an unusually large area, with 80- 120 mph gusts lasting over 30 minutes in areas near Cedar Rapids. o December 15, 2021 (Southeast Minnesota and Midwest) — By far the latest -in -the - season severe weather outbreak in Minnesota, this serial derecho traveled from southern Nebraska into Wisconsin, producing widespread 75 mph winds and 22 tornadoes across south-central and southeastern Minnesota, damaging buildings and homes, uprooting trees, and knocking out power. One man near Rochester was killed by straight-line winds. This event set a record back to 2004 for most reports of hurricane -force (74 mph) wind gusts. The storms were followed quickly by a strong cold front the dropped temperatures into the 20s and 10s F, as extreme non -convective winds associated with a powerful low- pressure area spread over the region. o May 12, 2022 (Corn Belt into western Minnesota)— Another powerful serial derecho with wind gusts of 85 to over 100 mph required just six hours to track from southern Nebraska to the Brainerd Lakes area of Minnesota. This massive event produced a dust storm from the dry conditions in western and central Minnesota, along with extensive damage to towns and rural properties. As of October 2023, this event was estimated to have produced over three billion dollars in damage across the region. 4.3.3.8. Future trends/likelihood of occurrence Ble For decades, the science was inconclusive about the connection between climate change and extreme thunderstorm winds or derechos, suggesting and trends in the frequency or intensity of these dangerous hazards would be short-lived and attributable primarily to "normal" variations in weather and climate patterns. Recent research, however, has suggested that a warming climate can influence the size and/or intensity of derechos and other extreme thunderstorm wind events. Physical modelling simulations of the August 91