Helene and NC, could that happen in the DMV?

[Anonymous]

Anonymous wrote:Only Cat 2, we did have Isabel hit 20 years ago.

https://www.washingtonpost.com/news/capital-weather-gang/wp/2013/09/18/remembering-hurricane-isabel-10-years-later-photos/

Are you saying it is unlikely that we’d get a category 4 hurricane here? With climate change, it seems big storms are becoming more common.

[Anonymous]

I think the topography of that area with mountains and valleys combined with the amount of rain contributed significantly to the flooding issue. I don’t think we’d see that sort of flooding, but more water in basements and issues in low-lying areas is certainly possible.

[Anonymous]

Anonymous wrote:I think the topography of that area with mountains and valleys combined with the amount of rain contributed significantly to the flooding issue. I don’t think we’d see that sort of flooding, but more water in basements and issues in low-lying areas is certainly possible.

Agree with this. Plus it had been raining for days prior to the hurricane so the area was saturated before the hurricane even came through.

[Anonymous]

Anonymous wrote:Always get flood insurance.

Or live on high ground.

[Anonymous]

Category 5. https://en.m.wikipedia.org/wiki/Hurricane_Isabel

[Anonymous]

Ashville is 2,134 feet above sea level.

Fairfax county is 300 feet above sea level.

So yes, it could happen here.

[Anonymous]

Anonymous wrote:

Anonymous wrote:Always get flood insurance.

Or live on high ground.

But the area in NC hit by Helene is high ground, no?

[Anonymous]

Anonymous wrote:There is a creek in the park behind my house, and FEMA updated their flood map to now include a small portion of the back of my house. The worst downpours so far have raised the creek to almost my property line, so it's possible my house could flood.

It wouldn't reach our roads though given the distance.

The advantage you have, then, that the people in those mountains didn't have is that you can get out. Their roads were washed out by that point.

The mountains make a huge difference. We don't have those. Could mountainous Virginia and West Virginia have this happen, though? Absolutely.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Always get flood insurance.

Or live on high ground.

But the area in NC hit by Helene is high ground, no?

Mud slides impacted some of those on high ground. These mountains are unusually steep, not just at higher elevations.

[Anonymous]

Anonymous wrote:

Anonymous wrote:There is a creek in the park behind my house, and FEMA updated their flood map to now include a small portion of the back of my house. The worst downpours so far have raised the creek to almost my property line, so it's possible my house could flood.

It wouldn't reach our roads though given the distance.

The advantage you have, then, that the people in those mountains didn't have is that you can get out. Their roads were washed out by that point.

The mountains make a huge difference. We don't have those. Could mountainous Virginia and West Virginia have this happen, though? Absolutely.

Good point. So many of their roads and bridges were washed out by the flash floods. The DMV being a flatter area might get flooding but not to the same extent.

[Anonymous]

Here's a good example of how the WNC flooding happened... and why it was so devastating. It's because of the effect of gravity from the elevation changes.

https://www.tiktok.com/@zack.massey/video/7420830944178736430

[Anonymous]

Anonymous wrote:Ashville is 2,134 feet above sea level.

Fairfax county is 300 feet above sea level.

So yes, it could happen here.

Sea level isn't relevant to Asheville: the issue was rain not ocean. We don't have the slope here for the kind of mudslides and rushing water that carried away homes in NC, and we don't have a constrained valley floor for the water to fill up. Coastal Florida is a better geographic comparison.

One thing to keep in mind is that paved surfaces worsen runoff and water management problems, because they concentrate water flow into narrow spaces and reduce the absorbent surfaces. This leads to dangerous fast-flowing water and flooding after storms. People hand-wave that as an "environmental" issue, but it's also a safety issue. When your local development boards are greenlighting a new building or road, speak up about runoff.

[Anonymous]

Mountains, people. They matter.

[Anonymous]

Anonymous wrote:

Anonymous wrote:I’d say yes, but to a lesser extent. There are tons of little streams across the area that all lead down to the bigger/Potomac. Any area facing 20 inches of rain in 24 hours will have damage.

Vermont and the TN/NC areas have towns built along river valleys. It only seems logical that these areas would get washed away. The homes in the mountains suffered tree damage and some flash flooding damage. That’s likely what most people in the DC area would suffer.

Also, the downstream effect would likely submerge a good portion of SE and SW DC.

Agree SE/SW would flood. I was also thinking the area near canal road/Macarthur blvd. it’s so close to the Potomac.

Yes. 100%.

When I drive to Audi Field, there’s a small road I sometimes take and the water is even with the road. There’s no barrier at all, and I could drive right into the water.

That place will flood for sure.

[Anonymous]

Anonymous wrote:Category 5. https://en.m.wikipedia.org/wiki/Hurricane_Isabel

I lived through this. We lacked electricity for three days. The water may have been questionable.

We did not flood. I live far from the river and up a hill on purpose.