Colonie Weather Online

A flood potential outlook  is issued by the National Weather Service every two weeks during the winter and spring. It refers to the potential for flooding across eastern New York State, southern Vermont, Berkshire County Massachusetts and Litchfield County Connecticut. The major river basins in this area are the Hudson, Mohawk and Housatonic.

During the winter months, freeze-up ice jams  may occur on area rivers. Freeze-up jams happen when extremely cold air temperatures occur over open water. This results in the rapid production of large amounts of river ice that can jam downstream. In places where the average temperature is zero or below for three or more consecutive days are susceptible to freeze-up jams.

The 5-Day Significant Flood Outlook  for the Northeast is a National Weather Service product that shows the likelihood of significant flooding in the next five days. Significant flooding is defined as flooding that affects roadways and structures, and may require evacuations or moving property to higher ground.

Flash Flooding: Flash flooding is a rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or creek above a predetermined flood level, beginning within six hours of the causative event (i.e., intense rainfall, dam failure, ice jam).

River Flooding: River flooding occurs when river levels rise and overflow their banks or the edges of their main channel and inundate areas that are normally dry.

Tropical Storms and Coastal Flooding: At any time of year, a storm from over the ocean can bring heavy precipitation to the U.S. coasts. Whether such a storm is tropical or not, prolonged periods of heavy precipitation can cause flooding in coastal areas, as well as further inland as the storm moves on shore.

Ice/Debris Jams: A back-up of water into surrounding areas can occur when a river or stream is blocked by a build-up of ice or other debris. Debris Jam: A back-up of water into surrounding areas can occur when a river or stream is blocked by a build-up of debris.

Snowmelt: Flooding due to snowmelt most often occurs in the spring when rapidly warming temperatures quickly melt the snow. The water runs off the already saturated ground into nearby streams and rivers, causing them to rapidly rise and, in some cases, overflow their banks.

Dam Breaks/Levee Failure: A break or failure can occur with little to no warning. Most often they are caused by water overtopping the structure, excessive seepage through the surrounding ground, or a structural failure.

Flash Flood Warning: A Flash Flood Warning is issued to inform the public, emergency management and other cooperating agencies that flash flooding is in progress, imminent, or highly likely. Flash Flood Warnings are urgent messages as dangerous flooding can develop very rapidly, with a serious threat to life and/or property. Flash Flood Warnings are usually issued minutes to hours in advance of the onset of flooding.

Flood Warning: A Flood Warning is issued to inform the public of flooding that poses a serious threat to life and/or property. A Flood Warning may be issued hours to days in advance of the onset of flooding based on forecast conditions. Floods occurring along a river usually contain river stage (level) forecasts.

Flood Advisory: A Flood Advisory is issued when a flood event warrants notification but is less urgent than a warning. . Advisories are issued for conditions that could cause a significant inconvenience, and if caution is not exercised, could lead to situations that may threaten life and/or property.

Coastal/Lakeshore Hazardous Message: Coastal/Lakeshore Hazard Message products provide the public with detailed information on significant coastal/lakeshore events. Coastal/Lakeshore events impact land-based and near shore interests along much of the United States coastline. This product can be issued as a watch, warning or advisory and follows the same "Be Aware, Be Prepared, Take Action" definitions as with other NWS WWA products. A Watch is issued when flooding with significant impacts is possible. Warnings are issued when flooding posing a serious threat to life and property is occurring, imminent or highly likely.

Special Weather Statement: Special Weather Statements provide the public with information concerning ongoing or imminent weather hazards, which require a heightened level of awareness or action, but do not rise to the level of watch, warning or advisory.

Flash Flood Watch: A Flash Flood Watch is issued to indicate current or developing conditions that are favorable for flash flooding. The occurrence is neither certain nor imminent. A watch is typically issued within several hours to days ahead of the onset of possible flash flooding.

Flood Watch: A Flood Watch is issued to indicate current or developing conditions that are favorable for flooding. The occurrence is neither certain nor imminent. A watch is typically issued within several hours to days ahead of the onset of possible flooding. In situations where a river or stream is expected to be the main source of the flooding, forecast confidence may allow for a Flood Watch to be issued several days in advance.