“Flood warning”的意思、由来-开放百科全书

A Flood warning is closely linked to the task of flood forecasting. The distinction between the two is that the outcome of flood forecasting is a set of forecast time-profiles of channel flows or river levels at various locations, while "flood warning" is the task of making use of these forecasts to make decisions about whether warnings of floods should be issued to the general public or whether previous warnings should be rescinded or retracted.

Description

The decisions made by someone responsible for initiating flood warnings must be influenced by a number of factors, which include:

National Flood Warning Services

The type of flood warning service available varies greatly from country to country, and a location may receive warnings from more than one service.

United Kingdom

Arrangements for flood warnings vary across the United Kingdom with several agencies leading on warnings for emergency responders and the public. The Environment Agency, Natural Resources Wales and Scottish Environment Protection Agency all undertake location specific flood warning activities for communities at risk depending upon the scale of flood risk, technical challenges and investment needed to deliver a reliable service.

Dissemination of flood warnings has moved towards a service whereby those at risk can pre-register to receive warnings by phone, email or text message from an automatic system, Floodline.^[1] Both warnings and updates about current conditions are also carried by local radio stations. In addition, live updates are carried by the Environment Agency's website,^[2] showing which locations have flood warnings in place and the severity of these warnings.

There is currently no flood warning system in Northern Ireland, but the Met Office does issue weather warnings. Flood risk management is the responsibility of Rivers Agency in Northern Ireland. Consideration will be given to the introduction of a warning system as part of the implementation of the EU Floods directive.

United States

In the United States, the National Weather Service issues flood watches and warnings for large-scale, gradual river flooding. Watches are issued when flooding is possible or expected within 12–48 hours, and warnings are issued when flooding over a large area or river flooding is imminent or occurring.^[3] Both can be issued on a county-by-county basis or for specific rivers or points along a river. When rapid flooding from heavy rain or a dam failure is expected, flash flood watches and warnings are issued.

In the U.S. and Canada, dissemination of flood warnings is covered by Specific Area Message Encoding (SAME) code FLW, which is used by the U.S. Emergency Alert System and NOAA Weather Radio network and in Canada's Weatheradio Canada network.

"Flood statements" are issued by the National Weather Service to inform the public of flooding along major streams in which there is not a serious threat to life or property. They may also follow a flood warning to give later information.^[4]

Example of a flood warning

The following is an example of a "Flood Warning." The South Chickamauga Creek is used as an example:

Example of a flood statement

Iowa Flood Center

The Iowa Flood Center at the University of Iowa operates the largest real-time flood monitoring system of its kind in the world. It includes more than 200 real-time stream stage sensors that feed data into the Iowa Flood Information System where data can be viewed, online, by disaster management staff and the general public. The stream stage sensors, mounted on bridges and culverts, use ultrasonic sensors to monitor stream and river levels.^[7]

References

1. ^{{cite web|url=http://www.environment-agency.gov.uk/homeandleisure/floods/38289.aspx|title=EA: Floodline Warnings Direct - our free flood warning service|website=environment-agency.gov.uk}}
2. ^{{cite web|url=http://www.environment-agency.gov.uk/homeandleisure/floods/31618.aspx|title=Flood warnings for England - GOV.UK|website=www.environment-agency.gov.uk}}
3. ^Burlingtonnc.gov National Weather Service: Watch, Warning, and Advisory Criteria
4. ^{{cite web|url=http://www.weather.gov/glossary/index.php?letter=f|title=Glossary - NOAA's National Weather Service|first=NOAA's National Weather|last=Service|website=www.weather.gov}}
5. ^{{cite web|url=http://www.srh.noaa.gov/data/warn_archive/MRX/FLW/0921_043406.txt|title=A flood warning archived at NOAA|website=noaa.gov}}
6. ^{{cite web|url=http://www.srh.noaa.gov/data/warn_archive/MRX/FLS/0922_100822.txt|title=A flood statement archived at NOAA|website=noaa.gov}}
7. ^{{cite web|url=http://iowafloodcenter.org/projects/stream-stage-sensor/|title=Iowa Flood Center|first=Iowa Flood|last=Center|website=iowafloodcenter.org}}