Public Information Statement
Issued by NWS Portland, ME

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000 NOUS41 KGYX 181102 PNSGYX Public Information Statement National Weather Service Gray ME 0700 AM EDT Tue Jul 18 2017 The National Weather Service has declared the week of July 17th through 21st, HURRICANE AWARENESS WEEK in New England. This is the second in a series of five public information statements to be issued by the National Weather Service Office in Gray, containing information on hurricanes and hurricane safety. HURRICANE WINDS AND TORNADOES Both hurricanes and tropical storms produce dangerous winds that can produce life-threatening conditions for anyone who is caught in them. Hurricane-force winds can easily destroy poorly constructed buildings and mobile homes. Debris such as signs, roofing material, and small items left outside can become flying missiles during hurricanes. Extensive damage caused by falling trees can lead to lengthy power and phone outages. Tropical circulations are classified based on the following wind speed criteria. Wind Speed Name Less than 39 mph Tropical depression 39 to 73 mph Tropical Storm 74 mph or greater Hurricane Hurricanes are further divided into 5 categories based on the destructive power of their winds. The scale used in hurricane classification is called the Saffir-Simpson Scale. Below is a list of the Saffir-Simpson Scale, the typical damage that occurs with storms of each category, and examples of each category of storm (at landfall). SAFFIR-SIMPSON HURRICANE SCALE CategoryDefinition-Effects 1 Winds: 74-95 mph (64-82 kt) No real damage to well-constructed buildings. Damage primarily to poorly constructed buildings and unanchored mobile homes, shrubbery, and trees. Also, some coastal flooding and minor pier damage is possible. Examples: Irene 1999 and Allison 1995. 2 Winds: 96-110 mph (83-95 kt) Some damage to building roofs, doors, and windows. Considerable damage to vegetation, mobile homes, etc. Flooding damages piers and small craft in unprotected moorings may break their moorings. Examples: Bonnie 1998, Georges (FL & LA) 1998 and Gloria 1985. 3 Winds: 111-129 mph (96-112 kt) Some structural damage to small residences and utility buildings, with a minor amount of curtain-wall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain may be flooded well inland. Examples: Katrina 2005, Fran 1996, Opal 1995, Alicia 1983 and Betsy 1965 4 Winds: 130-156 mph (113-136 kt) More extensive curtain-wall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Terrain may be flooded well inland. Examples: Hugo 1989 and Donna 1960 5 Winds: 157+ mph (137+ kt) Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Flooding causes major damage to lower floors of all structures near the shoreline. Massive evacuation of residential areas may be required. Examples: Andrew(FLORIDA) 1992, Camille 1969 and Labor Day-Florida Keys 1935 Hurricanes can also produce tornadoes that add to the storm`s destructive power. Tornadoes are most likely to occur to the right side of the hurricane track, however, they can also form in the rain bands, well away from the center of the hurricane. Studies have shown that more than half of land-falling hurricanes produce at least one tornado. In general though, tornadoes associated with hurricanes are less intense than those that occur in the Great Plains. Nonetheless, the effects of tornadoes, added to the larger area of hurricane-force winds, can produce substantial damage. Fortunately, hurricane-spawned tornadoes are infrequent in northern New England. QUESTION OF THE DAY: How often do we get hurricanes of each category in Maine and New Hampshire? The National Hurricane Center estimates "return periods" for the various categories of hurricanes for locations along the East and Gulf Coasts. In this determination, the likelihood of the center of a hurricane passing within 75 miles of a location is estimated. However, because northern New England does not have many strong hurricanes, it is difficult to determine the frequency of the stronger hurricanes. Category Return Period NH and SW ME 1 30 years 2 150 years 3 400 years FACT FOR THE DAY: The strongest winds in a hurricane usually occur on the right side of the track. If a hurricane makes landfall on the northern New England coast, the strongest winds will be to the east of the center of the storm. In contrast, most of the precipitation falls on the left side of the storm track. Hurricane Gloria, which made landfall over Long Island and southern Connecticut and traveled west of Portland, produced wind gusts of 70 mph in Portland, but produced only 0.41 inches of rainfall in the city. Here`s a list of the other topics covered in statements issued this week: Monday - Tropical Cyclones, Tropical Storms, and Hurricanes--The Basics Wednesday - Storm Surge and Marine Safety Thursday - Inland Flooding Friday - The Forecast Process--Statements, Watches, and Warnings For additional information about hurricanes and hurricane safety, visit the National Hurricane Center`s web site at: $$ Jensenius National Weather Service Gray...Maine NNNN is the U.S. government's official web portal to all federal, state and local government web resources and services.