Laserfiche WebLink
2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />4.3.3.7. Historical data/previous occurrence Bld <br />The Independence Day Derecho of <br />1977 <br />Although it did not affect Hennepin <br />County, the "Independence Day <br />Derecho of 1977" formed over west <br />central Minnesota on the morning of <br />Monday, July 41h. As the derecho <br />moved east-southeast, it became <br />very intense over central Minnesota <br />W f <br />f '-REST Bx-Wr, <br />r <br />rS <br />wr <br />COT <br />MN D T' <br />wp <br />c Dr .� <br />M 1 L S. <br />off <br />around midday. From that time through the afternoon, the derecho produced winds of 80 to <br />more than 100 mph, with areas of extreme damage from central Minnesota into northern <br />Wisconsin. <br />The derecho continued rapidly southeast across parts of Lower Michigan during the evening, <br />producing winds up to 70 mph and considerable damage before finally weakening over northern <br />Ohio around 1:30 AM on Tuesday, July 51h. This event was notable for affecting recreationist and <br />travelers out enjoying the Independence Day holiday. <br />West Metro to Northern Wisconsin Derecho of 1983 <br />On July 3, 1983, between 12:30 <br />and 13:20 local time, a complex of <br />extremely severe thunderstorms <br />affected a southwest to northeast <br />swath of Hennepin County. <br />Damage was most extensive from <br />eastern Lake Minnetonka, <br />through Maple Grove and <br />Champlin. The storms continued <br />into Anoka County and produced <br />the Twin Cities area's most recent <br />EF-4 tornado in Andover (most <br />recent as of January 2024). <br />Champhno <br />Dayton, Maple <br />f-,... <br />Grove, 7 houses <br />w crsawu <br />destro ed 4 <br />- ." �M..��. <br />ecei <br />reoeprril <br />lW4Y9 Sb°.Jr ik <br />moderate to <br />severe damage <br />FC, DRAW <br />„ <br />Lases <br />Knnetonka �rrv» nary a dip �lnr a ��%///%% i4ilk fad Nit <br />boats <br />l <br />capsized; %/�naH a ^ <br />GPd ya GaCw <br />Wayzata Bayi mJ1rJJar rroi Y <br />docks <br />deskroy^ed <br />5f r N1WMd Nm�& ,�rxa�uwwp�rw <br />, <br />WIW <br />Scattered wind damage <br />MEN MURK <br />Champlin: shopping i <br />maH severegy <br />d,arnaged; cars <br />thrown through <br />parking lot, $8.5 M' <br />(2015 USD) damage <br />r•r. tWTHQrvw,r <br />Extensive/continuous �T <br />Extreme straight-line winds <br />waned damage' <br />caused significant damage in a <br />southwest -to -northeast swath across Hennepin County. The storm complex raced northeastward <br />into Wisconsin during the next few hours, and aerial surveys conducted by the University of <br />Chicago found over 150 linear miles of continuous EF-1-equivalent straight-line wind damage, <br />with pockets of EF-2 damage —stretching from Carver County to Ashland, Wisconsin. The National <br />Weather Service Issued "Very Severe Thunderstorm Warnings" for the storm, to indicate winds in <br />excess of 75 mph, and sirens sounded throughout Hennepin County. <br />This storm remains (as of 2024) the most destructive severe convective storm event in the Twin <br />Cities Metropolitan Area, since the May 6, 1965, tornado outbreak. <br />