Texas Hurricane Beryl Landfall Oddly Raises Ominous Vermont Flooding Fears

Flood risk map for Wednesday. Yellow shading indicates
a 15 percent chance of enough rain to cause flash
flooding with 25 miles of a point on a map. That's a
higher risk than it might seem, and meteorologists
might upgrade this map to a higher risk around
Vermont depending on how future forecasts go.

As expected, Beryl regained hurricane status and came ashore near Matagorda, Texas early this morning, causing storm surges up to six feet deep and raking the area with powerful winds and torrential rains. 

Now that Beryl is inland, the 80 mph sustained winds it had at landfall will quickly diminish. However, like so many tropical storms and hurricanes, Beryl will potentially cause trouble over a possibly long path for a few days yet.

The remains of former tropical storms and hurricanes carry deep moisture for hundreds, even sometimes thousands of miles.  This can cause flooding a long distance from where they came ashore.

Such is the case of Beryl.

Its remnants will carry a flood risk this week from eastern Texas, through Arkansas, further north into the Midwest, the eastern Great Lakes and New England. 

That's where we come right here in Vermont and why local meteorologists are worried.

VERMONT EFFECTS

You might have noticed it's very warm and humid. Hasn't everyone? Beryl's remnants will bring an even bigger slug of atmospheric moisture to New England Wednesday and Thursday. 

Meanwhile, there will be some old weather fronts we'll call them boundaries for lack of a better word - hanging around that would serve as a focus to gather the moisture into torrential downpours. 

The main problem is those boundaries won't be moving much at all. That sets up the dreaded "training" in which repeated downpours move over the same spot like boxcars moving along railroad tracks. 

This puts us at risk for real trouble, again. It's certainly not definite yet, but something to keep a super sharp eye on for Wednesday and Thursday. 

For now, anyway, forecasters are focusing
the best chances of continued flooding
on Thursday around our region. 

The National Weather Service in South Burlington is painting an ominous picture in this morning's forecast discussion. Their worst (but plausible) case scenario is widespread two to four inches of rain, with potential streaks of four, six or even locally eight inches of rain if those training storms set up somewhere over Vermont.

"Those numbers, if they do materialize, would be comparable to the flooding event we experienced almost exactly a year ago," the NWS/South Burlington meteorologists wrote in that forecast discussion this morning. 

 That, indeed would be an unfortunately recipe for yet another Green Mountain State disaster. Not only would we have a number of cases of serious flash flooding and washouts, but it would once again possibly cause main stem river flooding.

I don't think Vermont farmers who occupy river flood plains could take another hit like they did last summer. So we'd better hope we luck out.  

And we might.  So far, anyway, this episode doesn't look like it would be as bad as last year's mess.  

It's impossible two or three days in advance like this where those boundaries would set up, and where the thickest moisture would gather. That could happen in Vermont, or off to our west, east, north or south. We don't know yet. 

It's certainly still possible we just get some pretty harmless brief downpours amid more miserable dankness and humidity Wednesday and Thursday, then we'd be done with it. Or, we could have some flash flooding problems here and there but nothing widespread. 

We'll have to wait for updated forecasts. 

PRECEDENCE

Vermont does have a history of tropical moisture colliding with fronts or boundaries to produce big time floods.

The vast majority of tropical storms and hurricanes that make landfall somewhere in the United States have very little or no effect on us here in Vermont. But a few do.  

The Great Flood of 1927 was caused by deep moisture drawn inland from an offshore tropical storm smacking up against a stalled north south aligned cold front to unleash those fatal downpours a century ago. 

Somewhat more recently, we've seen the effects distant tropical storms have had on us when the right ingredient come together.  

On July 31, 1995, weak Tropical Storm Dean splashed ashore in Texas, not all that much far north where Beryl made landfall this morning. 

Its remnant moisture streamed quickly north and east through the humid eastern United States until it encountered a stalled front across northern Vermont. The result was a disastrous flood, mostly in the Lamoille River valley on August 5-6 that year. . 

In July, 1997, a stalled weather front along the spine of the Green Mountains, combined with low pressure on Long Island, New York pumping moisture north, and the remnants of Tropical Storm Claudette, came together over Montgomery, Vermont.

The result was an intense flash flood that basically sent whitewater rapids through the heart of the town in the middle of the night.  

Not all Vermont floods are caused by tropical systems. The terrible flooding last July had nothing to do with a tropical storm. It was just a weather pattern that brought in record amounts of Atlantic moisture inland to do the job. 

BOTTOM LINE

This post isn't meant to scare anybody, but instead to alert you to what could happen. If it's enough to raise some worries among local meteorologists, it's worth spreading the word. 

I'm definitely hoping against hope that I will be able to post over the next couple days that today's column you're reading now was just a false alarm and you can get on with your life.

But just to be safe, now's the time to start thinking about what you would need to do if we had yet another flood disaster. If nothing else, it would be a good safety drill for what will be future floods in this chaotic climate changed world.