Laserfiche WebLink
2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />4.2.2.5. Geographic Scope of Hazard Blc <br />River flooding occurs across all of Hennepin County. Three major rivers create Hennepin County borders <br />on the northwest, south and east side. Those include the Minnesota, Crow, and Mississippi Rivers. In <br />addition, several creeks and streams across Hennepin County have a history of flooding, which have <br />caused damage to property. Some of those include the Minnehaha Creek, and Nine Mile Creek. All these <br />rivers and creeks are susceptible to early spring snow -melt flooding as well as summer and fall storm <br />seasons. <br />4.2.2.6. Chronologic Patterns <br />River flooding can occur because of both snowmelt and high precipitation events which makes the flood <br />season start from early spring to early winter. It of course depends on how warm we start to get in the <br />spring how early, to when we start to get below freezing in the winter. For example, if there is more than <br />average snowfall/snow depth tied together a spike in temperatures during the early spring, we are melting <br />snow without having a fully thawed out ground, making soil impervious, which increases the runoff and <br />subsequently increasing chances for flooding. <br />4.2.2.7. Historical Data/Previous Occurrence Bld <br />Floods have been documented all the way back to 1776 in Minnesota. However official American records <br />don't begin until 1873. Minnesota has seen twenty-four Disaster Declarations due to flooding, six of which <br />have been in Hennepin County. There have been no other naturally occurring incidents that are within <br />the scope of this plan. <br />1965 Flooding (DR-188) <br />• The Mississippi River at Fridley crested at 20 ft. on April 171h, 1965, which was 4 ft. over flood <br />stage. <br />On April 15, the Minnesota River at Savage crested at 719.40 ft., over 17 ft. above flood stage (702 <br />ft.), and 7 ft. above major flood stage (712 ft.). A day later April 16th, the Mississippi river at St <br />Paul crested at 26.01 ft., 12 ft. above flood stage (14 ft.) and 9 ft. above major flood stage (17 ft.). <br />The St Croix River at Stillwater followed suit with a record crest of 94.10 ft. on April 18, is 7 ft. <br />above flood stage (87 ft.) and 5 ft. above major flood stage (89 ft.). <br />1969 Flooding (DR-255) <br />• The Mississippi River at Fridley crested at 17.50 ft. on April 14, 1969, which was 1.5 ft. over flood <br />stage. <br />• Crow River crested at 16.5 ft. on April 11, 1969, which is 6.5 ft. over flood stage. <br />1997 Severe Flooding, High Winds, Severe Storms (DR-1175) <br />• The Mississippi River at Fridley crested at 17.10 ft. on April 10, 1997, which is 1.1 ft. over flood <br />stage. <br />40 <br />