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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />4.1.1.4.2. Infrastructure Destruction: Landslides can impact many kinds of critical infrastructure. <br />Linear infrastructure such as roads, highways, railroads, pipelines, electric power lines and <br />telecommunications cables are particularly vulnerable to slides that cross their paths. Water and <br />wastewater infrastructure is not only vulnerable to slides as a linear system but may also help <br />trigger landslide activity if a break occurs in water, sewer or storm sewer lines at sites that have <br />other susceptibility factors. Point infrastructure located at susceptible sites anywhere between <br />the crest to the foot of slopes are also vulnerable. <br />4.1.1.4.3. Property Damage: Homes and businesses have been damaged or destroyed by <br />landslides in Hennepin County and surrounding counties. Lack of detailed landslide investigations <br />and awareness in some cases have led to development on susceptible terrain. The fact that <br />landslides are not covered by insurance policies has led to often catastrophic financial losses for <br />homeowners and businesses that are hit. Expensive litigation has also often resulted from these <br />incidents between property owners and cities. <br />4.1.1.5. Geographic Scope of Hazard Blc <br />Landslide activity depends on certain localized factors (see above critical values) that result in an uneven <br />distribution of landslides across Hennepin County. In general, Hennepin County landslide activity occurs <br />in the valley walls of the Minnesota, Mississippi and Crow Rivers and their tributaries. Some of the exposed <br />glacial sediments and bedrock layers in these valleys are unstable and subject to precipitation or spring - <br />induced landslides. In the interior of Hennepin County, small landslides happen in steep slopes in glacial <br />sediments that are found along streams, ravines, lakeshores, and wetlands. Artificially steepened slopes, <br />often with disrupted soils and fills, also have been sites for landslides in Hennepin County. A Hennepin <br />County Landslide Hazard Atlas is in development and is set for release in late 2018. <br />4.1.1.6. Chronologic Patterns <br />Further work is needed among the Hennepin County landslide assessment team to develop <br />Chronological Patterns <br />4.1.1.7. Historical Data Bld <br />4.1.1.7.1. HISTORICAL RECORD: Hennepin County Emergency Management commissioned an <br />assessment of historic landslide activity in the county using archival data and historic news <br />accounts. There are around two dozen landslides in Hennepin County that were documented in <br />written accounts including a known location and date. <br />• June 19, 2014 (DR-4182) <br />• June 1, 2014 <br />• April 2014 <br />• May 22, 2013 <br />4.1.1.7.2. PRE -HISTORIC EVIDENCE: Hennepin County Emergency Management commissioned an <br />assessment of pre -historic landslide activity in the county using LiDAR (Light Detection and <br />Ranging) imagery. There are over one thousand sites in Hennepin County with landslide evidence <br />that have been discovered through imagery analysis. <br />15 <br />