ICE JAM FLOODING THREATENS NORTHEASTERN UNITED STATES DURING SPRING THAW

March 4, 2004 — Persistent cold, record-low temperatures and below normal stream flow are creating a dangerous threat for ice-jam flooding in the northeastern United States during this year’s spring thaw, according to the NOAA National Weather Service Eastern Region. (Click NOAA image for larger view of NOAA National Flood Risk Assessment as of Feb.27, 2004. Click here for latest map. Please credit “NOAA.”)

“The continued cold weather has increased the potential for river ice jams during the spring thaw. When Arctic air stays in an area for an extended period of time during the winter months and river flows are low, ice builds rapidly on the rivers. When the ice moves and accumulates, there is a high potential for flooding,” explained Dean Gulezian, director of NOAA Weather Service Eastern Region.

Gulezian explains that depending on the timing of the spring thaw, snowmelt runoff and rainfall, the ice jam condition can become dangerous. Each year, more deaths occur due to flooding than from any other severe weather-related hazard because people underestimate the force and power of water.

Most areas across central and northern New England and the interior mid-Atlantic region are reporting river ice ranging from one to three feet thick. A brief thaw in December created several ice jams in Vermont, upstate New York and interior Maine.

“Currently, two creeks in the Buffalo, N.Y., area are frozen in place with elevated water levels due to ice,” said Peter Gabrielsen, chief of the NOAA Eastern Region Hydrologic Service Division. We are concerned about these creeks overflowing their banks during the spring thaw, causing flooding. We expect this overall ice-jam flood threat to continue until the rivers are ice-free.”

Ice-jam flooding is a real concern for many communities. Union County officials used seven half-pound dynamite charges to break ice jams on Green Brook in North Plainfield, N.J., during the first week in February. The ice break-up was successful and residents’ homes were spared flood damage.

River ice conditions in coastal New England and the mid-Atlantic region are less serious as a result of rain in early February that eroded ice thickness. With the normal temperatures anticipated in the northeast and mid-Atlantic for early March, current river ice conditions will likely remain unchanged. Historically in the northeast, the most devastating winter and spring floods have been associated with a combination of heavy rainfall, rapid snow melt and ice jams.

“Our forecasters in impacted areas are on high alert as the spring thaw season begins,” said Gabrielsen. “Daily monitoring of the hydro-meteorological factors that cause flooding allow us to provide the best river forecasts and flood warnings.”

To keep updated on the late winter and spring conditions, the NOAA National Weather Service provides an updated National Hydrologic Assessment available on the Internet.

The NOAA National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. The NOAA Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy.

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Relevant Web Sites
NOAA Flood Risk Assessment

NOAA Northeast River Forecast Center

NOAA Significant River Flood Outlook

Media Contact:
Marcie Katcher, NOAA National Weather Service Eastern Region, (631) 244-0149