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| Flash flood risk has been upgraded to "moderate" in much of Vermont and surrounding areas, which makes at least some flash flooding pretty much guaranteed, with possible serious damage. |
The relative certainty of the event has increased. So has the expected rainfall amounts. Which means the flash flooding could end up being quite extensive here in the Green Mountain State.
This still won't be as bad or as long lasting as the cataclysmic flooding we saw exactly a year ago. But it will still be dangerous, damaging, even life-threatening in some areas.
Take this one seriously.
To nobody's surprise, the National Weather Service has issued a flood watch for all of Vermont except for our two southernmost counties, where rainfall should be lighter. The flood watch is in effect from 11 a.m. tomorrow through 11 a.m. Thursday.
Flood watches are also up for northeastern New York, most of New Hampshire and western Maine.
Let's break it all down:
TODAY/THIS EVENING
As expected, scattered thunderstorms erupted this afternoon around Vermont, and will continue into the evening before sputtering out.
Some of the most torrential thunderstorms hit central Vermont, along roughly a line from north of Middlebury, to near Montpelier and on toward St. Johnsbury. Some of these dumped a good inch of rain.
That's precisely the area that saw the heaviest downpours in last Saturday's round of thunderstorms. And it's the band across Vermont that could well see the heaviest rain from this upcoming flash flood episode.
So this piece is really bad.
WEDNESDAY
When you get up tomorrow morning, it won't seem so ominous. Sure, it will be incredibly humid. But there won't be much rain around.
That will change during the afternoon. As meteorologist Tyler Jankowski of WPTZ explained, a warm front associated with the remnants of Hurricane and Beryl will be trying to ever so slowly lift northward toward central Vermont.
At the same time, a weak cold front will try to move due south in Quebec. That puts central and northern Vermont between the two fronts. Between those two fronts, Beryl, with an assist from the Atlantic Ocean and the Gulf of Mexico, will provide the necessary water for torrential downpours.
The two fronts will conspire to make the air rise, so the downpours will break out, and pretty much keep running west to east between those two fronts.
As of this evening, the forecast for the heaviest rain runs from that Middlebury/Montpelier/St Johnsbury line. Which of course is the exact worst place it could be. We're talking three to six inches of rain in less than 15 hours.
That's enough to trigger some pretty damaging and dangerous flash flooding.
It's still quite possible the heaviest west to east band of flooding rains could set up a little north or a little south of the area I outlined. If that happens the flash flooding will be pretty much as bad as what I outlined, but it would of course be far northern Vermont or south central Vermont.
We'll see updates and adjustments tomorrow morning, I'm sure.
NOAA's Storm Prediction Center has upgraded its flash flood risk from slight to moderate across tomorrow for northeastern New York, the northern two-thirds of Vermont and northern New Hampshire.
That risk level almost guarantees there will be some reports of fairly substantial flash flooding. Again, not as bad as July 10, 2023, but bad enough.
The timing of this worries me, too. Flash flooding would probably start in earnest by late afternoon or evening. But it will likely peak after dark.
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| As if we don't have enough to worry about with flooding Wednesday, there's a low but definitely not zero chance of a tornado or two across New York and southern and central Vermont. |
Flash flooding and severe storms are more dangerous at night. If you're driving at night, you might not see the road under water or washed completely away until you hit it.
People in homes might not have a good read on how the water is behaving at night. And a hasty evacuation is dangerous in the dark.
Oh, and we have yet another potentially dangerous problem to deal with tomorrow. Former tropical storms are famous for spinning off tornadoes. Beryl created a couple dozen tornadoes in Texas, Louisiana and Arkansas yesterday.
Along and south of that warm front I mentioned, winds will change directions with height. So southern and possibly central Vermont is at risk for a few rotating thunderstorms. The biggest risk from these is damaging straight line winds. But we might also see a brief tornado tomorrow, especially from about Route 4 south.
Also, although far southern Vermont is outside the greatest flood risk area, thunderstorms could become intense enough to produce some instances of local flash floods.
THURSDAY
The heavy downpours will have departed by the time dawn breaks Thursday. Then we'll have to shift attention to the main stem rivers.
Some of them will go into flood stage, but it continues to look like rivers like the Winooski and Lamoille won't get nearly as high as they did in last year's epic disaster. Tuesday evening forecasts call for both rivers to stay below flood stage. I think future forecasts will increase the flood risk along those two rivers, but we should still fall far short of the horrors we saw in the Winooski and Lamoille valleys last July.
I think downtown Montpelier is safe, unless the forecast turns much, much worse. I think downtown Johnson should mostly escape trouble, again, fingers crossed.
WHAT TO DO
If you live in an area prone to flash floods that could force you to evacuate, put together a to-go bag tonight or early tomorrow. Include important documents, medications and other necessities. Think about what hoops you'd have to jump through to get your pets or elderly relatives out of harm's way.
Flash floods happen, well, in a flash, so you need to be nimble. Have ways to get weather warnings and advisories.
If you're told to evacuate by emergency officials, do it. And quickly. If they close a road, don't go around the barriers. If you can help it, don't wade into floodwaters. It's probably polluted and could get you sick.
If your basement is filling up with water, don't go down there. Basement walls and foundations are famous for collapsing in flash floods. That can trap you under water under debris if you're down there.
Charge your devices tomorrow morning. We could have power outages. Remember, there could be damaging thunderstorm winds in central and southern Vermont, or even a brief twister. Make sure you're ready to take shelter in a sturdy building if the National Weather Service issues a severe thunderstorm or tornado warning.
You want to be wicked careful driving. Please do NOT drive through flooded roads. You could stall or get swept away in just several inches of water. Also, the road might no longer be there under the water. It might have washed away.
BOTTOM LINE
This is yet another depressing "here we go again" moment. We have to face the reality that climate change has made weather extremes more likely.
I guess we've already had a lot of practice with this sort of thing. The main goal here is to prevent loss of life.
We are a bit at the mercy of this thing, although Vermont has taken steps to become more flood and disaster resistant.
Don't panic, but be sober. This too shall pass, and we'll have a breather again soon enough.
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