PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE GRAY ME 700 AM EST WED MAR 20 2013 The National Weather Service has declared the week of March 18th through 22nd Flood Awareness Week in Maine and New Hampshire, as well as the remainder of the United States. ...DETERMINING THIS YEAR'S CURRENT CONDITIONS AND FLOOD POTENTIAL... To help determine the potential for flooding, the National Weather Service Offices that serve northern New England continually monitor hydrological conditions throughout the region. River statements are issued daily and contain forecasts of the water levels for the major rivers in the area. Also, during the late winter and early spring the National Weather Service, in coordination with other federal and state agencies, power companies, and cooperative observers, surveys the snow pack across the area to determine the potential for spring flooding. There are several factors that contribute to the spring flood potential. These include the amount of snow on the ground, the amount of water contained in the snow (often referred to as water equivalent or water content), the density of the snowpack, and current river and stream levels. The water equivalent of the snowpack represents the water that will be released as the snow melts. The density of the snow is an indication of whether any melted snow (or subsequent rain) can be absorbed by the snowpack, or will be released. Another factor is how fast the snow will melt. As a general rule, the rate of melting is related to the temperature, humidity, and wind. Warm temperatures accompanied by high humidity and wind cause the greatest amount of melting. In addition, the state of the soil (frozen versus thawed and saturated versus unsaturated) determines whether any melting snow will be absorbed by the ground. Most importantly, however, the greatest contributing factor to flood potential is rainfall. In New England, major flooding does not occur due solely to melting snow. In addition, flooding can occur due to ice jams. Ice jams tend to occur in the spring when water levels on rivers start to rise and when there is still a significantly thick layer of ice on the rivers. The rising water in rivers causes the ice to break up, allowing large chunks of ice to start flowing. These chunks of ice can jam as they flow downstream. The jammed ice can then act as a dam and can prevent water and ice from flowing downstream. Ice jams are unpredictable and water behind ice jams can rise very quickly. In addition, when an ice jam breaks up, the resulting release can flood downstream areas very rapidly. Please note that the following information is based on snow surveys taken March 11th and 12th. Please refer to the following web site (in lower case) for the latest snow conditions in Maine and portions of New Hampshire The following web site (in lower case) provides up-to-date river and flood information. The following web site provides information on ice jams. CURRENT CONDITIONS (AS OF March 15): .Current snow depth and water equivalent...Snow depths across western Maine and New Hampshire range from 6 to 18 inches in southern and coastal areas to 18 to 30 inches in northern New Hampshire and the Western Mountains of Maine. The water equivalent of the snowpack ranges from 2 to 5 inches in the south and along the coast to 6 to 9 inches in the mountains. These values are about normal for this time of year. .Current snow density...The density of the snowpack general ranges from about .30 in the mountains to about .40 along the coast. A snow pack with a density of at or above .35 is considered "ripe" because it will hold no more water and any rainfall or melting with result in runoff. .Current river levels...Water levels and flows in rivers and streams throughout Maine and New Hampshire are on the higher end of the normal range for this time of year. .Forecast temperatures and precipitation...No major storms are expected in the next week and rivers are expected to remain at near normal levels. Temperatures over the next week are forecast to be near to slightly below normal. Precipitation is forecast to be near to slightly above normal. .River ice and ice jam potential...The warm winter temperatures have cleared many rivers of ice across southern and coastal areas of Western Maine and New Hampshire. On other rivers and streams where ice remains intact, ice thicknesses are below normal. .Flood potential outlook...The overall spring flood potential across Maine and New Hampshire remains is in the normal range. The snow pack is generally normal, rivers and stream levels are near normal, and the ground is saturated. Flooding is the top storm-related killer in the United States. Many fatalities occur because people attempt to drive through flooded roadways. Remember, if you encounter a flooded road, TURN AROUND, DON'T DROWN! $$ JENSENIUS/HAWLEY NATIONAL WEATHER SERVICE GRAY, MAINE NNNN