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Flood Watch, Flood Warning, Flood Advisory - what do they mean?
What is the difference between a Flood Watch and a Flood Warning issued by the National Weather Service?
Flash Flood Warning: Take Action! A Flash Flood Warning is issued when a flash flood is imminent or occurring. If you are in a flood prone area move immediately to high ground. A flash flood is a sudden violent flood that can take from minutes to hours to develop. It is even possible to experience a flash flood in areas not immediately receiving rain.
Flash Flood Warnings are changing to an Impact-Based format to improve public response. Read the factsheet.
Flood Warning: Take Action! A Flood Warning is issued when the hazardous weather event is imminent or already happening. A Flood Warning is issued when flooding is imminent or occurring.
Flood Watch: Be Prepared: A Flood Watch is issued when conditions are favorable for a specific hazardous weather event to occur. A Flood Watch is issued when conditions are favorable for flooding. It does not mean flooding will occur, but it is possible.
Flood Advisory: Be Aware: An Flood Advisory is issued when a specific weather event that is forecast to occur may become a nuisance. A Flood Advisory is issued when flooding is not expected to be bad enough to issue a warning. However, it may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.
Floods
Preparing for a flood is much like preparing for any other emergency, except:
Rain in Santa Clara County or on the higher coastal mountains around us, ocean storm surges, dam overflows, and water system backup have all caused floods in this valley in the past - and could do so again. And even a small-scale flood at home can cause a surprising amount of damage.
Check to see if your home is in a flood plain. If it is you may wish to take steps to prepare, including sandbagging when there are storm warnings.
After a Flood
If evacuated, do not return home until local emergency response teams declare that it is safe.
In addition:
Cleaning up after a flood or mudslide can require a lot of hard work, and can bring its own hazards. Professional remediation work may be needed.
A tsunami is a series of enormous ocean waves caused by earthquakes, underwater landslides, volcanic eruptions, or asteroids. They could happen anywhere along the coast.
To be prepared in the event of a tsunami, Ready.gov advises:
Maps of tsunami risk are available for all coastal areas of California, to use in planning evacuation routes.
Mudslides or Landslides
In California, mudslides can follow after drenching storms, especially in areas that recently burned in a wildfire. Earthquakes can also trigger a mudslide or landslide. Listen to your local media for flood watches, warnings and other travel advisories to find out if there is danger of mudslides. And as always, evacuate if ordered!
Watch for warning signs of debris flows or fast moving landslides:
Slower, more subtle signs of earth shifting may be visible in patterns of storm-water drainage on slopes (especially the places where runoff water converges) land movement, small slides, flows, or progressively leaning trees. Other signs are:
The USGS advises to:
After a Mudslide or Landslide
Coping After a Disaster
Floods or landslides are traumatic events! Take care of your mental and emotional health as well as your physical health - and your families and loved ones.
The text on this page is copyright Lise M. Dyckman and PlaneTree Health Library, licensed under Creative Commons CC BY-NC-SA 4.0. Linked contents are the responsibility of their creators or copyright holders.