Resolution_2025 Kittitas County Hazard Mitigation Plan

Home Browse Search

2025 Hazard Mitigation Plan Kittitas County, Washington Chapter 4: Hazard Identification and Risk Assessment 198 power lines, and communication towers can bring them down causing severe damage.260F 260 Table 4-150 outlines additional ice related hazards.261F 261 Table 4-150. Ice Related Hazard Type Definition Black Ice It is a deadly driving hazard. Black ice are patches of ice on roadways or other transportation surfaces that are not easily seen because it is often clear with black road surfaces. It is more prevalent during the morning hours after snow melts on the roadways and freezes overnight. Black ice can also form when roadways are slick from rain and the temperature reaches freezing levels. Ice Jams Long cold waves can cause rivers and lakes to freeze. A rise in the water level or a thaw breaks the ice into large chunks which become jammed at human-made and natural obstructions. Ice jams can act as a dam, resulting in severe flooding. Floods are addressed separately in this Plan. Frost Frost is the formation of thin ice crystals on the ground or other surfaces in the form of scales, needles, feathers, or fans. Frost develops under conditions similar to dew, except the temperatures of the Earth's surface and earthbound objects fall below 32°F. As with the term "freeze," this condition is primarily significant during the growing agriculture season. If a frost period is sufficiently severe to end the growing season or delay its beginning, it is commonly referred to as a "killing frost." Beca use frost is primarily an event that occurs as the result of radiational cooling, it frequently occurs with a thermometer level temperature in the mid-30s. Heavy Snow/Blizzards Winter storms are a combination of heavy snow, blowing snow, and/or dangerous wind chills and they have the potential of being life-threatening. Even though heavy snowfall and severe cold often accompany blizzards, they are not required. A winter storm is classified as a blizzard when there is a combination of blowing snow and wind resulting in very low visibilities. When strong winds pick up snow that has already fallen it is called a ground blizzard.262F 262 4.6.10.2. Hazard Location Winter Weather can occur anywhere in Kittitas County. The Pacific Ocean provides an unlimited source of moisture for winter storms. If the air is cold enough, snow falls over the State of Washington. As the moisture rises into the mountains, heavy snowfall is capable of closing mountain passes and causing avalanches. Refer to the avalanche section of this Plan for further details. Cold air from the north has to filter through mountain canyons into the basins and valleys to the south. If the cold air is deep enough, it can spill over the mountain ridge. As the air funnels through canyons and over ridges, wind speeds can reach 100 mph and combining these winds with snow results in a blizzard. 4.6.10.3. Hazard Extent/Intensity Often called the “deceptive killer”, winter weather can be life threatening and can cause substantial damage to infrastructure, property, and agriculture. Furthermore, many deaths are attributed to indirect causes of winter weather (e.g., icy roads lead to an increase in traffic accidents). The extent of damage caused by winter weather depends on the type of winter weather, strength, and location. 260 National Oceanic and Atmospheric Administration, National Severe Storms Laboratory. (n.d.). Severe Weather 101: Types of Winter Weather. Retrieved from https://www.nssl.noaa.gov/education/svrwx101/winter/types/. 261 National Weather Service. (n.d.). Ice Storms. Retrieved from https://www.weather.gov/safety/winter-ice-frost. 262 National Oceanic and Atmospheric Administration, National Severe Storms Laboratory. (n.d.). Severe Weather 101: Winter Weather Basics. Retrieved from https://www.nssl.noaa.gov/education/svrwx101/winter/.