VIENNA, Austria - It looks like a color-coded terror alert scale - and meteorologically speaking, that's exactly what it is. With climate change making conditions more unpredictable, national weather services from across the European Union have joined forces to create - a new Web site providing up-to-the-minute information on "extreme weather" across the continent.

The initiative, managed by Austria's Central Institute for Meteorology and Geodynamics, is designed to give Europeans a single source for details on flash floods, severe thunderstorms, gale-force winds, heat waves, blizzards and other violent weather that poses a threat to life or property.

It also issues 24- and 48-hour warnings for heavy fog, extreme cold, forest fires and "coastal events" such as high waves or severe tides.

"In one glance you will be able to see where in Europe the weather might become dangerous," organizers said Saturday in a statement.

The service is similar to the United States' National Weather Service, which posts on its Web site conditions, warnings and forecasts for all 50 states.

Although the European site officially will launch in Madrid, Spain, on March 23 - World Meteorological Day - it is already live on the Web in test form.

Under the new pan-European warning system, white means missing or insufficient data; green means no imminent threat; yellow signifies potentially dangerous weather; orange warns of dangerous conditions; and red means very dangerous, "exceptionally intense" weather.

Pictograms and photographs showing lightning bolts, churning floodwaters and other catastrophic scenes also pop up "to make the general public more conscious or aware" of a particular threat, the organizers said.

Users click on maps to get details on current conditions or forecasts of violent weather for the next day. There are also links to a country's national weather service.

The Network of European Meteorological Services includes 20 countries and covers land stretching from Portugal to Sweden. Not every nation in the region is contributing, but the site hopes to bring others online eventually.

The Web site "pulls together all the warnings from the official national weather services," said Michael Staudinger of the Vienna weather institute.

It seemed to be accurate on Saturday, at least for Vienna, which was buffeted by gale-force winds gusting to 50 mph. The system churned out a yellow high-wind warning for the area and provided details in German and English.