Resolution 7478 hazard mitigation

Home Browse Search

2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan Volume 2 — Hazard Inventory Humid heatwaves pose significant dangers to those working, recreating, or living outside. Increases in these dangerous conditions will affect larger proportions of the population, as the risk moves from those most vulnerable, to the general population, and even those in excellent physical condition. Following are some consequences expected with climate change in Hennepin County: • Less reliable and more dangerous lake ice • More periods of bare/snow-free ground, allowing frost to penetrate to great depths during cold outbreaks. • Expansion of the heavy rainfall season, leading to enhanced peak stream flows, and altered timing of normal flow regimes. • Increased runoff and flash -flooding as the largest events intensify and become more common. • Water infrastructure damage from intense rainfall events • Agricultural stress, from shifting crop ranges, heat, drought, and extreme rainfall • More days with high water vapor content and heat index values • Greater summer cooling costs, more days requiring cooling. • New invasive species, both terrestrial and aquatic, especially those acclimated to warmer climates or those that were cold weather limited. • "Hyper -seasonality," as warm conditions develop during the "off-season," leading to bouts of heavy rainfall or severe weather, followed by wintry conditions. • Increase in frequency of freeze -thaw cycles, as winter is increasingly infiltrated by warm conditions. Some positive benefits of a changing climate might include fewer automobile accidents and damage as more winter precipitation falls in the form of rain rather than snow or ice. However, warmer winters doesn't necessarily mean rain instead of snow, it could mean more ice storms, which would lead to dangerous driving conditions and power outages due to down power lines. Also, rain falling in the winter can be disastrous if it is followed by sharply colder air and a "flash -freeze." Additionally, summertime air temperatures are extremely likely to begin increasing in the decades ahead, and possibly before 2030. When these hotter summers pair with normal dry swings in the climate, they will increase drought severity and water demand, while also increasing the potential for wildfire (see drought section of risk assessment). Some new research (as of 2023) indicates that extreme windstorms associated with thunderstorms may become more probable, larger, and possibly more intense as the world continues warming. These studies indicate that, as a result, a given extreme wind event may have the ability to affect more people and more property than in the past —not accounting for the growth and the expansion of Hennepin County's population. In recent years, smoke from wildfires has degraded air quality, occasionally to dangerous levels in Hennepin County. Climate models project that wildfires and downstream smoke infiltration will become more common as northern forests are weakened by warming winters, more severe heat waves, and even precipitation extremes. Increased smoke particulates are a health hazard for everyone, but disproportionally affects those with respiratory challenges, limited mobility, other health conditions, and those who cannot shelter from the smoke. 56