W I N T E R STORM HAZARD DESCRIPTION

Transcription

1 W I N T E R STORM HAZARD DESCRIPTION... 1 LOCATION... 2 EXTENT... 2 HISTORICAL OCCURRENCES... 4 SIGNIFICANT PAST EVENTS... 4 PROBABILITY OF FUTURE EVENTS... 5 VULNERABILITY AND IMPACT... 5 HAZARD DESCRIPTION Winter storms that threaten Otsego County are a virtually guaranteed yearly since the County is located at relatively high latitudes resulting winter temperatures range between 0 degree F and 32 degree F from late October until Mid- April. In addition, the County is exposed to large amounts of moisture from both the Great Lakes and the Atlantic Ocean. Otsego County is vulnerable to two different winter storm types: Northeaster and Lake Effect storms. The first type, the Northeaster usually forms off the U.S. East Coast near the Carolinas then follows a track northward along the coast, until they blow out to sea. Occasionally these storms are large enough to cover the entire State of New York, but primarily affect eastern and southern New York. The second type of storm, Lake Effect, occurs when moisture is picked up from the Great Lakes and then blown across the western-central portion of New York State, often leaving huge quantities of snow. Both storm types are known for high snow accumulations and high winds, causing major damages, usually by disrupting transportation, limiting communications, and causing power outages. As shown in Figure 9-1, on average, the area experiences inches of snow annually. S T R A T E G I E S T O M I T I G A T E T H E I M P A C T S O F N A T U R A L D I S A S T E R S O N H U M A N L I F E A N D P R O P E R T Y

2 Figure 9-1. NY Annual Normal Snowfalls NY Annual Normal Snowfalls LOCATION Because winter storm events are not confined to specific geographic boundaries, all existing and future buildings, facilities and populations are considered to be exposed to this hazard and could potentially be impacted. EXTENT Table 9-1 displays the magnitude of severe winter storms. The wind-chill factor is further described in Figure 9-2. This is an index developed by the National Weather Service, although the chart is not applicable when temperatures are over 50 or winds are calm. Wind chill temperature is a measure of how cold the wind makes real air temperature feel to the human body. Since wind can dramatically accelerate heat loss from the body, a blustery 30 day would feel just as cold as a calm day with 0 temperatures. Table 9-1. Magnitude of Severe Winter Storms Winter Weather Advisory Winter Storm Watch This alert may be issued for a variety of severe conditions. Weather advisories may be announced for snow, blowing or drifting snow, freezing drizzle, freezing rain, or a combination of weather events. Severe winter weather conditions may affect your area (freezing rain, sleet or heavy snow may occur separately or in combination). Page 2 Otsego County Hazard Mitigation Plan Update

3 Winter Storm Freezing Rain or Freezing Drizzle Sleet Blizzard Frost/Freeze Wind Chill Severe winter weather conditions are imminent. Rain or drizzle is likely to freeze upon impact, resulting in a coating of ice glaze on roads and all other exposed objects. Small particles of ice usually mixed with rain. If enough sleet accumulates on the ground, it makes travel hazardous. Sustained wind speeds of at least 35 mph are accompanied by considerable falling or blowing snow. This alert is the most perilous winter storm with visibility dangerously restricted. Below freezing temperatures are expected and may cause significant damage to plants, crops and fruit trees. A strong wind combined with a temperature slightly below freezing can have the same chilling effect as a temperature nearly 50 degrees lower in a calm atmosphere. The combined cooling power of the wind and temperature on exposed flesh is called the wind-chill factor. Based on 272 previous occurrences recorded from 1950 to 2012, the County has been subject to blizzards, winter storm watches, warnings, freezing rain, sleet, snow and wind chill. Figure 9-2. Wind Chill Chart Otsego County Hazard Mitigation Plan Update Page 3

4 HISTORICAL OCCURRENCES From 1950 to 2012, the NCDC and SHELDUS have recorded 272 events in Otsego County. Events range from heavy snow storms, ice storms, and winter mix. Some of the most severe storms have caused damages in excess of $3.5 million (2012 dollars), 6 injuries, and 1 fatality (avg. 1 fatality in 10 counties). SIGNIFICANT PAST EVENTS 6 March 1996 A winter storm formed over the Carolinas and tracked up the coast, bringing heavy snow to central New York. Snowfall accumulations ranged from 6 to 12 inches by the time the snow tapered off on the evening of the 7th. During the height of the storm, many accidents were reported due to poor visibility, including one in which an elderly couple was killed and one person injured in a collision in Lansing (Tompkins County). In Onondaga County, one man was killed and one injured in a two-car accident in Marcellus. Two people were injured near Rome in Oneida County when their car drove off the road, and six people were injured in Homer, Cortland County, when a tour bus drove off Interstate 81 in near zero visibility. 4 April 2003 A stationary front was west to east across Pennsylvania during the 3rd and 4th of April. Areas of low pressure moved along the front bringing precipitation to upstate New York. A large area of high pressure, centered over Hudson Bay Canada helped to keep cold air at the surface. The morning of the 5th low pressure moved northeast to Erie, Pennsylvania then to northeast New York that evening. A trailing cold front brought with it an end to the precipitation from west to east. Patchy freezing rain was across these counties first the night of the 3rd into the 4th. At this time the freezing rain was most widespread in Northern Oneida County. Steady widespread freezing rain started during the day of the 4th across Oneida, Onondaga, and Madison Counties. During the evening of the 4th colder air spread further south into the Finger Lakes and northern Susquehanna Region. This changed moderate rain to freezing rain in these areas especially at the higher elevations. Across northern Oneida County the freezing rain changed to snow. The snow accumulated up to five inches. Ice accumulations were mostly a quarter to half an inch with a few locations up to an inch. The Schuyler County Emergency Manager reported an inch of ice across most of the county. Tens of thousands of electricity customers were without power, some for up to a week. States of emergencies were declared for most of these counties. 13 February 2007 A low pressure system developed over the southern plains on February 12th, and intensified rapidly as it neared the East Coast on the night of the 13th. The storm then continued to strengthen as it moved up the Atlantic Seaboard during the day on February 14th. The storm spread snow into central New York beginning the evening of Tuesday, the 13th. The snow continued heavy at times through the 14th and gradually tapered off to snow showers on the 15th as the storm pulled northeast past the Gulf of Maine. Some sleet mixed with the snow for brief periods of time. The snow became heavy with near blizzard conditions at times over the Finger Lakes and central southern tier of New York during the early morning hours of the 14th. The heavy snow and near blizzard conditions shifted east to the upper Susquehanna Region of New York and western Mohawk Valley by the afternoon and evening of the 14th. Gusty winds to 40 mph developed behind the storm late on the 14th and through the 15th which led to considerable blowing and drifting snow. This hampered snow plowing and snow cleanup operations. As a result, many roads and highways were closed during the height of the snowstorm. Many counties and municipalities Page 4 Otsego County Hazard Mitigation Plan Update

5 declared snow emergencies. Storm total snowfall amounts across much of central New York ranged between 15 and 30 inches. Less snow fell in Sullivan County, New York where more sleet was reported. This kept snowfall amounts down between 8 and 12 inches in this area. The heaviest snowfall from this storm occurred in Delaware and Otsego counties where between 2 and 3 feet was common. The highest snowfall was reported in Roseboom where 39 inches of snow occurred and Springfield where 38 inches fell. The weight of the snow caused several roofs to collapse. PROBABILITY OF FUTURE EVENTS Based on the available data for previous occurrences of winter storms, the probability of a future event is highly likely, with a winter storm probable within the next year. VULNERABILITY AND IMPACT Economic impact may be felt by increased consumption of heating fuel, which can lead to energy shortages and higher prices. House fires and resulting deaths tend to occur more frequently from increased and improper use of alternate heating sources. Fires during winter storms also present a greater danger because water supplies may freeze and impede firefighting efforts. In general, the study area is at risk with snow hazards and extreme cold temperatures, as well as ice. According to NCDC, total loss (in 2012 dollars) is estimated at $18,514,747 in damages over the 62 year recording period giving an approximate loss of $300K in damages annually (Table 9-2). LOCATION NUMBER OF EVENTS Table 9-2. Historic Damage Estimates by County PROPERTY CROP PROPERTY (2012 DOLLARS) CROP (2012 DOLLARS) Otsego Co. 272 $9,424,671 $64,947 $18,343,592 $171,155 Total Losses Source: NDCD and SHELDUS $9,489,617 $18,514,747 Frequency of return based on 272 events over the recording period gives a probability of four to five storms each year. Despite the potential harm from a winter storm event, based on the level of risk and previous occurrences for winter storms in Otsego County, the impact for winter storm is substantial with fatalities resulting. Otsego County Hazard Mitigation Plan Update Page 5