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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />4.1.3.3.1.3. Energy pipelines: Gas and other pipelines are vulnerable to the effects of <br />frost. According to data from the Pipeline and Hazardous Materials Safety Administration <br />(PHMSA), 82% of cold weather failures of distribution pipelines in the US (1984 through <br />2014) were caused by frost heave. <br />4.1.3.3.1.4. Communications: Buried fiber optic cables are susceptible to impacts from <br />frost. This occurs when water that has infiltrated the fiber optic conduit freezes. The most <br />vulnerable areas where sites were cables were shallow or exposed near bridges. While <br />freezing has no impact on copper cables, fiber optic cables may be bent by the expansion <br />of the ice. Various levels of signal degradation may occur, including complete failure. As <br />a countermeasure, some communication companies have injected their conduit with <br />anti -freeze compounds. <br />4.1.3.3.1.5. Structural damage: Frost heave of soils can cause significant damage to <br />structures including cracked foundations or slabs and other effects from ground <br />movement. <br />4.1.3.3.1.6. Transportation: Roads and highways are impacted frost action. Differential <br />frost heaves are creating blisters in pavement that leads to cracking and potholes. Frost <br />can block proper drainage and lead to additional problems. Road load -bearing capacity is <br />affected by freeze -thaw cycles. <br />4.1.3.3.2. SECONDARY CONSEQUENCES: <br />Frost induced breaks in gas or oil pipelines can cause fires or explosions. <br />4.1.3.4. Potential for Cascading Effects <br />4.1.3.4.1. Specific sites. Deep frost can impact buried infrastructure that carry water, wastewater, <br />energy or communications causing service interruption by freezing or by physical damage. Frost <br />heaving can also cause damage to buildings and other structures. These damages are highly <br />dependent on localized conditions leading to impacts that area variable from address to address. <br />Frost depth impacts may be widespread but spotty. <br />4.1.3.4.2. General areas. Deep frost can create a frozen and temporarily impervious layer of soil <br />across wide regions which limits infiltration of snow -melt water and rainwater in springtime. This <br />additional runoff worsens springtime flooding across river basins and stream watersheds. <br />4.1.3.5. Geographic Scope of Hazard Blc <br />All areas of Hennepin County and the State of Minnesota are vulnerable to soil frost during winter months. <br />Minnesota and the adjacent state of North Dakota are the center of deep frost activity in the 48 <br />contiguous United States. While frozen soils are routine in all parts of Minnesota, problems occur when <br />frost penetrates deeper than normal. The Minnesota State Building Code (MSBC) Rule 1303.1600 places <br />construction frost depth in Hennepin County at 42 inches (106.7 centimeters). <br />24 <br />