 |
| Aerial shot of devastation in Lyndonville yesterday, taken by Vermont Public's Kyle Ambusk. There's a renewed risk of more flash flooding in Vermont today. |
While I'm cautiously optimistic we might not see anything quite as extreme as Tuesday morning in Vermont's Northeast Kingdom, any added flooding and damage is exactly what we don't need right now.
Plus the areas that were hardest hit Tuesday are most at risk of renewed flooding today. Soils there pretty much cannot absorb more water, so a downpour will almost automatically translate to renewed flash flooding.
Areas of Vermont that have avoided heavy rain over the past couple of days have less chances of seeing flash flooding. But if the rain falls hard enough in any given location, it can open new areas of flooding that had remained untouched at least for the past couple weeks.
DIFFERENCES
Today's weather risk is much different from the one that unfolded early Tuesday.
Tuesday's Northeast Kingdom calamity was caused by an upper level low that locked in the intense thunderstorms over the region for four or five hours.
I strongly doubt will see rainfall totals like the six to more than eight inches of rain that slammed the Northeast Kingdom Tuesday. But in areas already soaked, it will only take as little as an inch or two of rain to set off more flash flooding.
Today's potentially torrentially downpours will move, albeit at a rather grudging pace. They are all traveling in tandem with a more traditional "normal" summertime weather disturbance moving in from the west.
This disturbance isn't in much of a hurry, which opens up a rather long, six to 12 hour time frame where we potentially can have torrential downpours.
One thing that is similar to Tuesday is that rainfall amounts will vary widely. Some towns will see as little as a quarter inch of rain or even a little less, which of course translates to no flooding. However, a short distance away, there could be much, much more, which would put flash flooding in play.
That situation would lead us to the kind of thing we had yesterday. Town A will be high and dry, while adjacent Town B is facing road washouts and potentially big time property damage.
DANGER ZONES
The trouble with virtually all Vermont floods, and flood risks, is we don't get much notice of what's to come. In those big river floods in the Midwest you read about from time to time, you know a couple days in advance a flood crest is coming, so you have time to evacuate, and get some of your stuff out of the way.
Here, we don't have that luxury.
I'm writing this at around 8 a.m. Wednesday. The risk of flash flooding starts in less than six hours and continues into the evening. I - and everyone else - has no friggin' clue if and where the heaviest rain will set up, and where and if new flash floods develops.
You'll pretty much find out when and if a flash flood warning is issued for a particular spot. You'll have minutes to react, and that's being generous. We'll just have to wait and see how the day unfolds.
Remember, this will be localized stuff. The whole state won't flood. There just might be a few unlucky towns and small regions, once again.
As noted, the Northeast Kingdom is most at risk for trouble today. The biggest thing to watch is whether more than one downpour hits a particular spot. If you just had a big downpour a half hour ago and another big burst of rain starts to move in, that's when you need to start worrying at least a little.
In steep terrain where the worst of the rains hit Monday and Tuesday, we'll also need to be on the alert for landslides. I already saw one instance of that along Route 2 near St. Johnsbury yesterday.
Even if we luck out and don't have much in the way of flash flooding, it's wicked humid out there. That humidity will actually increase a little more as we go through the day. Those oppressive conditions, and rainfall will only hinder flood cleanup in the Northeast Kingdom.
The risk of severe thunderstorms with damaging winds is not quite zero, but it's very low. Flash flooding is the focus today.
TIMING
There were already some showers around this morning. Nothing heavy, nothing scary as of 8 a.m. The showers will increase in coverage and intensity as we go through the day.
The heaviest rains will peak between 2 and 8 p.m. today, then slowly wind down.
BEYOND TODAY
Hot, humid weather is on tap for Thursday and Friday. There might be some widely scattered thunderstorms a couple of which might have torrential downpours. But those will be few and far between and the risk for new flooding those days is pretty low.
The risk of additional flooding could ramp up again Saturday and Sunday, so we'll keep an eye on that as we get closer to the event.
No comments:
Post a Comment