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The Advanced Hydrologic Prediction Services

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This week, the National Oceanic and Atmospheric Administration (NOAA) and FEMA are once again partnering for National Flood Safety Awareness Week.  Each day of National Flood Safety Awareness week, we will provide key information related to flood hazards, and ways to protect yourself and your property.

The influences of weather, water and climate on our daily lives and economic well being are manifold, and at times profound. A fact highlighted by the devastating and heartrending events of the past few years.

NOAA's National Weather Service (NWS) provides weather, water, and climate forecasts and warnings to protect life and property and enhance the national economy.  To fulfill this important mission, skilled NWS meteorologists and hydrologists use state-of-the-art science and technology to monitor and predict weather, water and climate impacts for our nation and its citizens 24 hours a day, every day of the year.

Floods are our nation’s most costly natural disaster and, on average, is the leading cause of severe weather-related deaths.  Floods have claimed an average of 94 lives a year and $10.2 billion in economic damages in the decade 2001-2010 alone. Watch The Water’s Fury (Quicktime file) to see the power of water.

While floods are not preventable, the loss of life and property can be reduced significantly with more timely and accurate forecasts and warnings.  An important means by which the NWS produces and distributes flood and water resource forecasts and information is through the Advanced Hydrologic Prediction Service, known as AHPS (pronounced A-Haps).

AHPS is an ongoing effort by the NWS to continue modernizing its hydrologic services and provides new information and products through the infusion of new science and technology.  It is a web-based suite of accurate and information-rich forecast products in graphical form that enables government agencies, private institutions, and individuals to make more informed, risk-based decisions to mitigate the dangers posed by floods and droughts.

Some examples of the products and information from AHPS include: hydrographs combining current water level observations from the U.S. Geological Survey with NWS river forecasts; extended range (i.e., 90-day) probabilistic forecasts conveying the chance a river will exceed minor, moderate, or major flood levels; inundation maps for water levels from flood stage through the flood of record, depicting where and how deep the flood waters will be in a neighborhood or community thereby enabling emergency managers and other decision makers to preposition people and resources to most effectively mitigate the impacts of a flood; historical floods impacts, and much more.

The broad reach of AHPS extends the range of forecasts from short-term (up to 6 hours) to long-term (out to weeks and months) and provides the public with more detailed and accurate answers to the following questions:

  • How high will the river rise?
  • When will the river reach its peak?
  • Where will the flooding occur?
  • How long will the flood last?
  • How long will the drought continue? and
  • How certain is the forecast?

AHPS forecast products and information support decisions regarding the operation and management of flood-control structures.  Emergency management officials at the Federal, state, territorial, tribal and local and state levels use these forecasts to fight floods, evacuate residents, and to take other measures to mitigate the impact of flooding.  Also, these products are used by a wide range of people, such as barge and dam operators, power companies and municipal water supply officials, recreational users, farmers, households, businesses, and environmentalists. Anyone and everyone who makes water-based decisions benefits from AHPS.

Get ready, be prepared and be FloodSmart before the flood starts.

Stay current with flood risk in your area with the latest official watches and warnings at For detailed hydrologic conditions and forecasts, click the "water" tab.

Last Updated: 
06/16/2012 - 14:43

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