Feb 21, 2012; 12:47 PM ET
Spring flooding is a natural cycle following a hard, snowy winter. However, in areas where deep snowcover lingers rapid flooding poses a greater risk to lives and property. (Photos.com image)
Up to several feet (90 cm or more) of snow in recent weeks in southeastern Europe is a concern for flooding through March, if the wrong storm were to come along.
The snow contains locked up moisture, in some cases on the order of several inches (100 mm) or more.
The longer the snowpack lasts into the spring, the greater the risk of rapid meltdown and flash flooding.
As the cold eases and the sun climbs higher in the sky over the coming weeks, the snow will melt gradually in most of Europe.
However, even in gradual thaw conditions, some minor flooding is to be expected, beginning with ice jams, then strong flows and high water levels on streams and rivers in general.
According to Long Range Weather Experts Paul
Pastelok and European Weather Expert Jason Nicholls, "A gradual warm-up is forecast for western Europe in March with near-normal temperatures forecast for northern Europe."
Areas of western and northern Europe also have little snowcover compared to other locations, so flooding is a lower risk.
The area of greatest concern for spring flooding is southeastern Europe and includes the Danube watershed and other rivers.
"This is where there is a much deeper snowcover than normal and cold air is likely to hang on the longest into the spring," Pastelok and Nicholls said.
If any rain storm there were to come along, tapping warm, moist air from the Mediterranean Sea, it could cause the snowcover to liquify suddenly.
Such a situation occurred in part of the northeastern United States during January of 1996.
Up to several feet of snow melted in a matter of hours as a couple of inches (50 mm) of rain swept through the region with air temperatures in the 50s and 60s (10 to 18 degrees Celsius) and dew point temperatures almost as high.
Small mountainside streams turned into raging torrents and major, normally slow-moving rivers in broad valleys rose rapidly.
At present, there is no particular storm lurking on the maps, but there is a risk for flooding in part of southeastern Europe if such a storm were to come along until the bulk of the snowcover has diminished.
Senior Meteorologist Jim Andrews contributed to the content of this story
.
No comments:
Post a Comment