Wednesday, February 28, 2007

High Water Alert...

The National Weather Service has issued a "Statement as of 3:45 PM EST today... Flood Watch in effect from Thursday evening through Friday evening... "

AccuWeather also has its own take on the situation as illustrated by their nice graphic at the top of the page.

It looks like the lower Delaware River Basin will get all rain, between 1 and 2 inches. But the upper Delaware might get freezing rain and snow, and if so that will reduce the potential for flooding on the tributaries up there. Most of the snow is melted away here in the piedmont region, but the upper watershed has a fair amount of snow pack and the river has a normal amount of ice clogging it.

As the NWS puts it: "The ground remains frozen in many areas. This frozen ground, in combination with a very ripe snow pack in some locations and heavy rain, could cause flooding in low lying areas and small streams from the Poconos south to northern Maryland and Delaware, and east into central New Jersey. River and stream ice could add another complexity to the situation as water levels rise and the ice begins to move."

A "very ripe snowpack" is an intersting way to put it.

Right now the Delaware River at Belvidere (and othe locations) is running a little below normal for this time of year.

In my opinion it would be better if the upper watershed received rain to wash away some of the "ripe snow pack" and decrease potential for flooding on any subsequent storm. The river could easily take a few inches of rain without going out of its banks, although that may not be so for some tributaries.

About half the record Delaware River floods have occured as a result of heavy rain on top of frozen ground, snow and ice, the most recent example being April 2005. The other half have been caused by hurricanes or tropical storms. (See the July 11 2006 post)

I believe we'll get through this season without any significant flooding.

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