Last Week's Austin, Texas Storm Super Wild, Super Weird

From Facebook, photo of damage at Austin Wildlife
Rescue after the massive supercell and oxymoronically
named large microburst in the city last week. 

 Texas is known for its, well, Texas sized storms.

But even by those standards, what hit the Austin, Texas area was absolutely wild.  I guess the "Keep Austin Weird" slogan applies to the weather there as well. 

A fast developing, giant supercell roared over the city on May 28.   It almost, but didn't quite produce a tornado. But it might as well have, given the damage it caused. There were also no other storms around it, just an isolated, big, bad one, Very bad,

It produces  one of the worst microbursts, one of the heaviest rainfall rates and some of the worst hail to ever hit Texas, and maybe the United States for that matter. 

MICROBURST

As the name implies, microbursts hit a relatively small area.  On average, they'll do their damage in a one to two mile diameter area. 

Microbursts, as noted,  are often are as dangerous as tornadoes, as the storm in Austin demonstrates.  Some microbursts carry wind gusts of 100 mph, which is the equivalent of an EF-1 tornado. (For comparison the tornado that hit in Middlebury, Vermont, in March, 2021, seriously damaging one home and causing lighter damage to several others, was an EF-1

The National Weather Service explains what causes these dangerous thunderstorm microbursts.:

Strong updrafts suspend a bunch water droplets in the upper portion of the storm. At some point, the updraft is no longer able to sustain all that stuff, so it lets them go like a clumsy waiter dropping a tray load of dishes. 

When the "tray load of dishes" hits the ground, all hell breaks loose, like it did in Austin, writ large.

The Austin area microburst, despite its name, was pretty huge.  

The damage path was about ten miles long, with a path ranging from one to 2.5 miles wide. Maximum sustained winds within the microburst were probably between 65 mph and 85 mph, with a few embedded higher gusts. The Austin-Bergstrom International Airport had a 77 mph gusts, reports KXAN.

REAR FLANK DOWNDRAFT

To make matters worse, the supercell had something called a rear flank downdraft in which winds reached up to 75 mph.  As KXAN reports:

The National Weather Service mapped out damage
from the May 28 supercell and big microburst.
Area in red is damage from the microburst, yellow
is from a real flank downdraft. The darker
the color, the worse the damage was.

"A rear flank downdraft is caused by pressure patterns within a supercell thunderstorm that force cool mid-level winds quickly down to the ground before getting pulled back into the rotating thunderstorm."

Rear flank downdrafts are common in in supercells, especially strong ones like that in and around Austin last week.

Like the microburst, the rear flank downdraft moved southeastward, in tandem with the microburst that was just to the north and east of the rear flank downdraft.

This downdraft and its 75 mph wind blew right through downtown Austin.  

DAMAGE

The wind, as you'd imagine, knocked down a lot of trees and power lines. About 180,000 residents lost power.  Winds of that speed tend not to seriously damage well-constructed homes, but it was enough to tear shingles off roofs and break windows  I'm sure several homes and other buildings suffered damage from falling trees

Windows and doors were reported broken by the wind at Austin-Bergstrom airport and the Texas State Capitol building in Austin. The canopy over gas pumps at an Austin service station collapsed onto cars beneath it whose owners were taking shelter from the hail. Thankfully, only minor injuries were reported. 

The largest oak tree in Austin's first Black cemetery toppled over and damaged several headstones.

The wind drove large hailstones sideways, damaging the siding on countless homes, Roofs, crops, trees and gardens were also blasted and wrecked.  

Intense flash flooding swept cars off roads and left at least one person dead. At least five others had to be rescued from submerged cars.

 The spot where the microburst first hits the ground is usually where the worst damage is.  In Austin's case, there might have been a train of microbursts, one after another. Or, the supercell thunderstorm that caused it had much more rain and hail to unload than most storms. 

It was also a single thunderstorm and not a line. While all hell was breaking loose on the north side of Austin and its suburbs, it was a pleasant evening with sunshine in the southern end of Austin.

Austin is weird. 

VIDEOS

Compilation of some of the storm scenes in Austin: As always, click on this link to view, or if you see the image below, click on that,

More images, mostly of the flooding from the microburst last week in Austin: Again, click on this link to view, or if you see image below click on that, 

 

BREAKING: Tornado Confirmed In Benson, Vermont

6:15 PM FRIDAY UPDATE

A possible microburst over Lake Champlain Thursday. 
Although the picture looks tornadic, it wasn't. However
meteorolists confirmed a Thursday tornado in Benson, Vermont. UPDATE

CORRECTION: It's actually NOT two tornadoes, just one. I was confused by apparently two site visits the National Weather Service conducted.

So to be clear, there is only ONE confirmed Vermont tornado from Thursday, the one near Benson.

PREVIOUS DISCUSSION

Meteorologists with the National Weather Service in South Burlington confirmed that a tornado touched down in Benson Thursday.  

Thursday's  EF-0 tornado packed winds of 85 mph. It was a narrow, but long-tracked tornado by Vermont standards. It appears to have only been 20 yards wide, but had a path length of 12.3 miles.  It's possible the tornado lifted, but later touched back down again. 

But true to form in this disastrous summer in Vermont, the meteorologists couldn't determine if there were more touchdowns with this tornado. They couldn't access areas to investigate due to flooded roads. 

The tell-tale sign of a tornado was that trees and power poles fell in different directions. That indicates there must have been the swirling winds associated with the twister.  Nobody was hurt, but several power poles were snapped near the intersection of Routes 30 and 144. 

The meteorologists also investigated an area of extensive wind damage in Shoreham. They determined that a microburst, not a tornado caused the destruction. All the trees that fell toppled over toward the northeast, meaning there was no swirl of a tornado involved. 

Proving that microbursts can be as destructive as tornadoes, the meteorologists noted up to 75 large trees uprooted, metal torn from roofs and siding torn from houses,  and a mile wide area of corn was flattened. Fencing simply disappeared and  could not be found. 

The National Weather Service estimated top winds in the microburst reached 85 mph.

I'm not sure if the meteorologists are investigating other areas of damage associated with Thursday's storms, but I'll keep you posted. 

Believe It Or Not, Wet Start To August Parts Of Vermont, But Dry Times Returning

Burlington, Vermont got socked with quite a thunderstorm last evening, which contributed to what is a surprisingly wet start to August.  

The thunderstorm that passed through St. Albans, Vermont
last evening glows in the post-sunset dusk as it continued
to move east toward the Northeast Kingdom.

It appears a microburst rolled through Winooski, a good chunk of Burlington and through South Burlington last evening, downing trees and power lines and causing a kind of havoc-strewn evening around there. 

A huge tree fell on Burlington's Intervale Avenue, and a gust of 51 mph was recorded at the National Weather Service office in South Burlington.

Microbursts tend to produce really big gushes of rain, and this storm was no exception. It dumped 1.15 inches of rain at the NWS office.

The result of this, Tropical Storm Isaias last week and another strong thunderstorm a couple days before that very wet beginning of August, at least in Burlington. So far this month, 5.25 inches of rain has fallen on Burlington. 

Even if not one more drop of rain comes down this month, Burlington will end August with rainfall of 1.3 inches more than average.

Elsewhere in Vermont it hasn't been as wet.  Up here in St. Albans, we had more of a garden variety thunderstorm last evening.  It produced about two thirds of an inch of rain, and winds gusted to perhaps 30 mph during the height of the storm. 

Also, rainfall from Isaias wasn't as heavy in eastern Vermont as it was west of the Green Mountains. 

The weather is about to take a decided turn toward much drier weather, possibly lasting a couple weeks, so I don't think we're going to set any rainfall records this month. There will be more rain, but I doubt it will be as intense as the first half of the month has been.

A cold front is suppressing moisture well to our south.  But that moisture is pooling in the Mid-Atlantic States today. That's bringing a big flash flood risk, especially in a roughly 100-mile diameter circle centered around Washington DC.

This makes me worried about flood-prone Ellicott City, Maryland, which has suffered two extreme flash floods in the past few years. 

Already, early this morning, there were some swift water rescues ongoing in northern Virginia with people trapped in cars on a flooded thoroughfare.

Back up here in Vermont, high pressure that will linger in southern Quebec will probably keep us dry and warm through the upcoming weekend.  But the humidity will be much lower, and it won't be torrid by any stretch of the imagination.

Daytimes will be in the low 80s for the most part and nights will be relatively comfortable for sleeping through the end of the week