What do higher levels in the Potomac River after Isaias mean for DC region?

It often takes a day or two after a big storm for large bodies of water, such as the Potomac River in the D.C. region, to see the potential for flooding.

Could Isaias, which came through the area earlier this week, still have an impact this weekend?

Isaias immediately caused some area streams to flood, but when it comes to local rivers, that normally takes some time.

“Around the D.C. area, the Potomac would be one of the larger rivers that takes a few days to rise and fall,” said Charles Walker, associate director for data at the Maryland, Delaware and D.C. USGS Water Science Center.

He said that the impact from the storm earlier this week has raised the water levels about half a foot.

“The discharge for the Potomac is running higher than normal,” Walker said.

But he said that unless there’s a flash storm with a significant amount of rain in the next few days, the risk of flooding is extremely low.

As of Thursday night, no such storm is in the forecast.

“The conditions prior to the storm were dry, so the flooding was minimal,” Walker said. “It will eventually come back down.”

He said dry conditions before the storm combined with the fact that it moved quickly through the area made the impact less severe for the Potomac.

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