5.4.2 Severe Winter Storm / Extreme Cold
SECTION 5.4.2: RISK ASSESSMENT – SEVERE WINTER STORM / EXTREME COLD 5.4.2 SEVERE WINTER STORM / EXTREME COLD This section provides a profile and vulnerability assessment for the severe winter storm and extreme cold hazards. HAZARD PROFILE This section provides profile information including description, extent, location, previous occurrences and losses and the probability of future occurrences. Description For the purpose of this HMP and as deemed appropriated by the County, most severe winter storm hazards include heavy snow, blizzards, sleet, freezing rain, ice storms and can be accompanied by extreme cold. Since most extra-tropical cyclones, particularly northeasters (or Nor’Easters), generally take place during the winter weather months (with some exceptions). Nor’Easters have also been grouped as a type of severe winter weather storm in this section. In addition, for the purpose of this plan and as consistent with the New York State Hazard Mitigation Plan (NYS HMP), extreme cold temperature events were grouped into this hazard profile. These types of winter events or conditions are further defined below. Heavy Snow: According to the National Weather Service (NWS), heavy snow is generally snowfall accumulating to 4 inches or more in depth in 12 hours or less; or snowfall accumulating to 6 inches or more in depth in 24 hours or less. A snow squall is an intense, but limited duration, period of moderate to heavy snowfall, also known as a snowstorm, accompanied by strong, gusty surface winds and possibly lightning (generally moderate to heavy snow showers) (NWS, 2005). Snowstorms are complex phenomena involving heavy snow and winds, whose impact can be affected by a great many factors, including a region’s climatologically susceptibility to snowstorms, snowfall amounts, snowfall rates, wind speeds, temperatures, visibility, storm duration, topography, and occurrence during the course of the day, weekday versus weekend, and time of season (Kocin and Uccellini, 2004).
[Show full text]