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| Bear Pond Books in Montpelier posted to social media this highly ironic and sad photo of books floating in the water in the ruined store,. |
While we're recovering and taking stock, let's see how we got here in the first place.
STICKY WEATHER
Weather patterns have been pretty "sticky" all year. Instead of the usual variability - a few days of cool, wet weather followed by a several sunny days - we kept getting stuck under the same old same old.
In May and the first half of June, it appeared Vermont was heading into a "flash drought." A flash drought is one that develops in weeks instead of the usual months. Everything was drying out fast amid weeks and weeks of sunny, warm, windy weather with very little rain. Drought conditions were officially declared in northern Vermont.
Then the weather pattern flipped in mid-June. Suddenly Vermont was cloudy and literally sticky with humidity. Rain showers became a seemingly constant presence. At first, we loved it. Drought relief!
An upper level storm system has sat stubbornly to our west and north most of the time since mid-June, somewhere over or near the Great Lakes.
The arrangement set up a near-constant flow of very humid air from the Gulf of Mexico and the Atlantic into Vermont and the rest of New England. Little disturbances kept spinning through that upper low, southward through the Great Lakes, then eastward through the Midwest, then northeastward toward us.
When each disturbance turned to the northeast, they would grab on to that moisture flow and wring it out over New England as showers and storms. Meanwhile, we wilted under constant high humidity, without the breaks of cool, dry weather we normally see in early summer.
The drought-relieving shower didn't quit. The ground got wetter and wetter through the last week of June and the opening week of July. We had less and less capacity to handle downpours. Local flash floods began to pop up.
By Friday, July 7, the ground was wet enough, and rain was locally heavy enough to cause destructive local flash floods in towns like Hardwick, Worcester, Killington and Bridgewater.
That was the preview, The stage was set for the disaster.
A POTENT STORM
One of the disturbances passing around that upper level low late last week and weekend had more oomph to it than the previous ones. And, the disturbance decided to be a slow poke. There just wasn't enough speed in the jet stream to fling the system in and out of the area.
On Sunday, the disturbance settled over Pennsylvania and New York, tapping a huge flow of moisture from the Atlantic Ocean. That's why eight inches of rain fell in the lower Hudson Valley of New York on Sunday, causing a devastating flood there.
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| A flood-ravaged corn field near Cambridge, Vermont. |
Out ahead of this band, scattered torrential thunderstorms roamed Vermont Sunday, further pre-soaking the ground.
By then, weather forecasters around here were downright scared. The same conditions that afflicted the Hudson Valley were about to move into Vermont. Except in a more intense fashion.
Essentially, this storm pulled an atmospheric river of wet air off the Atlantic, moving it northwestward from the southeastern New England coast toward the wall that is the Green Mountains.
The air was forced to go up and over the mountains, wringing the moisture out of the air and dumping it over the spine of the Green Mountains. In the end, those mountains received four to eight inches of rain, with locally more than nine inches, in basically just a day.
We were screwed.
By Monday morning, chaos reined in southern Vermont, and it was spreading northward. The initial band of torrential rain that trashed southern and central Vermont weakened and moved on late Monday morning.
But we weren't finished yet.
Shortly after noon, you could see the rest of the doom on radar. A new river of wet air had set up, and it was aimed at central and northern Vermont. The skies opened. Montpelier and many other contraband northern Vermont communities were doomed.
UNIQUE RIVERS, UNIQUE RESULTS
Like every other flood disaster I can think of, the destruction was spotty. Some areas escaped the worst of it. Others lived a nightmare. Part of it was the type of waterways involved.
Smaller rivers are "flashier" than larger ones. Flashier means they respond really quickly to heavy rains and rise quickly. When the rain quits, the water goes down fast.
This is oddly what saved the flood prone Mad River Valley. The initial torrent of rain Monday morning put the Mad River into minor flood stage. Then the rain diminished for awhile, and the river quickly began to recede. The new afternoon and evening rain put the Mad River back above flood stage, but that brief interval of receding water provide room for the new onslaught.
People near the Winooski and Lamoille Rivers weren't so lucky.
Those smaller rivers drained into the Winooski and Lamoille, making them continue rising even during that interval of lighter rains midday.
Then the real torrents hit. I was in Montpelier during the worst of the downpour. I was stunned by how torrential it was. Visibility was down to less than a mile at times, kind of like during a heavy snowstorm.
But this was rain, lots of it. Smaller rivers overwhelmed upstream towns. The Stevens Branch, one of the smaller, '"flashier" rivers immediately became wild, completely overwhelming Barre, seemingly in minutes.
That water, along with runoff from countless smaller brooks and streams all poured into the Winooski at once.
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| Interior of a flood-wrecked liquor store in Johnson, Vermont. |
The river at Montpelier, already high, went from manageable looking at 4 p.m. to submerging Montpelier by 6 p.m. In just a half hour starting around 6 p.m., the Winooski at Montpelier went from minor to major flood stage.
There was no time to evacuate. People were stuck in second and third story apartments, and in cars along on and off ramps of Interstate 89 in Montpelier.
Another thing that made things tough was the length of time the WInooski stayed at such high levels. Not only was the crest higher than in Tropical Storm Irene in 2011, it lasted much longer. Irene's flood was up and down and over within 12 hours.
This time the Winooski peaked at around 21 feet near midnight, dropped a couple inches before rising to its ultimate crest of 21.35 feet at mid-morning Tuesday. From there, it only slowly receded.
The experience was similar along the Lamoille, although its timeline was a little later than the Winooski. While all eyes were on Montpelier, the Lamoille at Johnson peaked at 21 feet, the highest since the Great Flood of 1927.
The Lamoille ended up devastating Johnson, and Jefferson and Cambridge.
CLIMATE CHANGE
I can't say climate change "caused" this disaster. I bet it had a big influence, though.
A warmer atmosphere can hold more water than a cooler one. That probably increased the capacity of the air to dump rain on Vermont early this week..
Had there not been climate change, but all other factors stayed the same, we very likely would have had a destructive flood anyway. But a warmer atmosphere probably made it rain harder than it otherwise would have.
Which meant the flooding was deeper than it otherwise might have been. That makes a big difference in structural damage. A foot of water inside a business or house is much more expensive to fix than six inches.
That "stuck" weather pattern I talked about earlier is another climate change suspect.
A growing number of climate scientists also think these "stuck" weather patterns we're seeing have to do with a warmer world. That said, that's not a universal belief among climate scientists, and a debate on the issue continues.
But the scientists who are suspicious of the climate jet stream link think that decreased spring time snow cover in North America is helping create Greenland Blocks.
A Greenland Block is a strong area of high pressure that forms over or near that island. The high pressure causes an atmospheric traffic jam that stalls weather systems upstream all the way back through North America.
That Greenland Block has been there since late June at least, and seems to have peaked in intensity this past weekend and early week.
It didn't help that the Atlantic Ocean, where our storm moisture came from, is warmer than normal, very likely at least partly due to climate change. When the water is warmer, more moisture can evaporate into the atmosphere.
That added to the rain making capacity of that sort of atmospheric river that slammed into Vermont Monday.
THE SKEPTICS
Climate skeptics, some of whom have already reached out to me, point out that Vermont has always had big floods. Including big summer torrents.
They're right.
David Ludlum's classic "The Vermont Weather Book" has tons of examples. Big flash floods struck at least parts of Vermont in July, 1811, July, 1830, in Rutland in June, 1947, and a statewide mess in June, 1973.
There skeptics will also point out that big floods sometimes come in groups. Also true. Vermont endured major, destruction floods in 1927, 1936 and 1938, for example.
But the sheer number and volume of floods in recent years suggests something is up. The Great Flood of 2023 is most often compared with the floods of Tropical Storm Irene in 2011.
However, the list of big Vermont floods since the mid 1990s is huge. Major, destructive floods hit the state in 1995, 1996, 1997, 1999, 2002, 2007, 2008, 2010, 2011, 2013, 2018 and 2019.
The more recent floods of 2011, 2013 and 2019 were especially destructive. And remember in 2011 it wasn't just Irene. In the spring, the Lamoille River Valley was badly trashed by near-record flooding, and Lake Champlain reached by far its highest level on record, causing millions of dollars in damage. sermon.
This just demonstrates that dangerous flood events are becoming more common in Vermont, and that trend will continue, it seems.
PLANNING HELPS
Vermont State officials were already thinking long and hard about climate change in the aftermath of Irene's floods in 2011.
They were in a build back better mood. So replacement culverts were bigger than the original. New bridges had extra reinforcements. The State Office Complex, horribly damaged by Irene, was repaired and fortified against subsequent floods.
As Anne Galloway in New Republic points out, this planning a decade ago might well have helped tremendously with this new disaster. The magnitude of the flooding in 2011 and 2023 was overall similar. But infrastructure damage this go around - while huge - doesn't seem as bad as in 2011.
The Vermont Agency of Transportation managed to bring the number of roads closed down to 29 by Tuesday. Nine bridges in Vermont were wrecked by this week's flooding, compared to 200 bridges in 2011, Galloway/New Republic reports.
This proves that we can mitigate some of the effects of climate change through careful planning and building. But we can't escape those effects.
Back in 2021 ProPublica and the New York Times analyzed all counties in the United States to figure out which are the safest and least safe from climate change.
The analysis said that the two safest counties in all of the United States were Lamoille and Orange counties in Vermont. Both counties suffered extreme damage in this week's flood.
So much for a climate refuge.
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