Flash Floods Kill 3 in Colorado; Dangerous 93L Developing in Gulf of Mexico

By: Dr. Jeff Masters , 3:06 PM GMT on September 12, 2013

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Devastating flash floods swept though numerous canyons along the Front Range of Colorado's Rocky Mountains Wednesday night and Thursday morning, washing out roads, collapsing houses, and killing at least two people. The floods were triggered by widespread torrential rains of 4 - 6" that fell in less than twelve hours, thanks to a flow of extremely moist air from the southeast that pushed up against the mountains. These sort of upslope rain events are so-named because as the air flows uphill, it expands and cools, forcing the moisture in it to fall as rain. Balloon soundings from Denver last night and this morning recorded the highest levels of September moisture on record for the station. The total precipitable water (PW), which is how much water would fall at the ground if the entire amount of water vapor through the depth of the atmosphere was condensed, was 1.33" at 12Z (8 am EDT) on September 12, and 1.31" at 00Z September 12. The previous September record was 1.23", set on September 10, 1980. Balloon soundings began in 1948. Wednesday night's rainfall was heaviest near Boulder, Colorado, where a flash flood watch continues through Thursday evening. Though rainfall amounts today are not expected to be as great as on Wednesday, the soils are saturated, and additional flash flooding will occur today as an upper-level low centered over the southern Great Basin continues to pull a moist southeasterly surface flow of air across Eastern Colorado. A map of Boulder flood zones and detailed history of previous floods in the area may be found here.


Figure 1. Flooding in Boulder, Colorado on Wednesday evening, September 11, 2013. Photo posted by brandish on Instagram @photogjake.


Figure 2. Radar-estimated rainfall for the Colorado's Front Range from the September 11 - 12 flash flood event. Rainfall amounts of 6 - 8" (dark rad colors) were indicated near Boulder (circle with a "+" symbol), and confirmed by rain gauge measurements.


Video 1. Flooding in Boulder, Colorado at 36th and Colorado Street on Wednesday night, September 11, 2013.

Dangerous 93L developing in the Gulf of Mexico
A low pressure system (Invest 93L) over the Southwestern Gulf of Mexico's Bay of Campeche is generating heavy rains over the Yucatan Peninsula and adjacent waters as it moves west-northwest at about 5 mph. Radar loops from Mexico show that 93L has a pronounced rotation and is developing low-level spiral bands, and there is a strong possibility that the Air Force hurricane hunter plane scheduled to investigate 93L Thursday afternoon will find that a tropical depression has formed. Satellite loops show only a modest area of heavy thunderstorms, but these are steadily growing in intensity and areal coverage. The atmosphere is unusually moist, ocean temperatures are a very warm 29 - 29.5°C (84 - 85°F), and wind shear is a moderate 10 - 15 knots. These favorable conditions for development are expected to continue through Monday, according to the latest SHIPS model forecast. The computer models predict a landfall location along the Mexican coast between Veracruz and a location a few hundred miles south of the Texas/Mexico border by early next week. The storm is expected to maintain a forward speed of about 5 mph during the coming five days, and this slow motion will potentially allow 93L enough time to intensify into a hurricane before landfall. The high levels of moisture and slow motion of 93L make it a very dangerous rainfall threat, and I expect rainfall amounts of 5 - 10 inches will affect portions of the Mexican coast between Veracruz and Brownsville, Texas over the next five days. An added danger is the presence of tropical disturbance 90E in the Eastern Pacific Ocean, on the other side of Mexico. If 93L intensifies sufficiently, it could draw in the moisture from 90E across Southern Mexico, resulting in torrential rains on both the Pacific and Atlantic sides of Southern Mexico. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave 2-day odds of development of 60% and 5-day odds of 80%.


Figure 3. Latest satellite image of Tropical Depression Ten.

Humberto peaks in intensity
Hurricane Humberto is headed northwards over the far Eastern Atlantic, and has likely peaked in strength, with 85 mph winds. Humberto is listed in NHC's preliminary Best-Track data repository as having achieved hurricane strength at 8 am EDT on September 11, which would tie it with Hurricane Gustav of 2002 for latest appearance of the season's first hurricane since 1941. Satellite loops show that Humberto is well-organized hurricane with a distinct eye, but the storm has moved over waters cooler than 26°C, and wind shear has risen to 20 knots, which will likely cause weakening over the next few days. Humberto is not expected to be a threat to any land areas.

Gabrielle heads towards Canada
Tropical Storm Gabrielle is headed northwards to Canada after bringing 40 mph winds and just over an inch of rain to Bermuda on Tuesday night. Satellite loops show that wind shear has ripped up Gabrielle, leaving the storm with almost no heavy thunderstorms, and exposing the low level circulation to view. Wind shear is expected to rise to an extremely high 45 - 70 knots on Friday as Gabrielle encounters a trough of low pressure, which will likely destroy the storm. Gabrielle's remnants will likely bring heavy rain to the Canadian Maritime Provinces on Friday and Saturday.

Jeff Masters

After the Rain (mtnwoman67)
Lots of rain in Colorado for weeks. Last evening's setting sun gave us a great show east of us.
After the Rain

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449. txjac
Quoting 445. Luisport:
KDVR FOX31 Denver ‏@KDVR 3m

#Boulderflood report: Volunteer firefighter stuck in tree in Lefthand Canyon since 5AM just rescued. Serious injuries …
Link


OMG, this is so horrible. People need to get off the roads .. keep safe to any on the blog who are in Boulder
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Quoting MrMixon:


Perhaps... but rain continues to fall. This might be predecessor to a larger slide. Numerous slides have been reported throughout the county. If I find a photo of a larger slide I'll post it for you, alright?




Small solace for the families of the three people who have died today and the numerous people who are still trapped in homes or vehicles.



Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.

I just don't think most people understand that Colorado is really a desert. 1.23" of PW might not sound like much to those of us in the SE, where PW's of near 2.00" are normal, but the Front Range doesn't have well developed drainage systems, so it doesn't take much to cause some fast and deadly flash floods. My so went to CU for his Master's and lived there for about 10 years, and boulder has some of the worst weather in the US, with heat waves, droughts, flash floods, tornadoes, and higher winds than most place is the US that have been hit by major hurricane have experienced. I'd certainly like to hear what's happening along the front range. Unfortunately, pictures that Dr. Master chose to post of a moron in a drainage channel during a flash flood, and a bunch of college students playing in flood waters aren't helping any when it comes to any sympathy for the people who died in the floods and landslides. I wish they would be removed and have pictures of actual damage shown, not pictures of people who's bike rides were interrupted.
Member Since: October 2, 2004 Posts: 0 Comments: 15958
AccuWeather.com ‏@breakingweather 1 min
60 people evacuated from campground due to flash flooding by Lakewood, NM reports emergency manager Link
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TXNT23 KNES 121756
TCSNTL

A. TROPICAL DISTURBANCE (93L)

B. 12/1745Z

C. 19.7N

D. 93.9W

E. FIVE/GOES-E

F. T1.5/1.5/D1.0/24HRS

G. IR/EIR/VIS/SSMIS

H. REMARKS...3/10 BANDING FOR DT=1.5. MET AND PT AGREE. FT IS BASED
ON DT.

I. ADDL POSITIONS

12/1443Z 19.7N 93.6W SSMIS


...SALEMI
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KDVR FOX31 Denver ‏@KDVR 3m

#Boulderflood report: Volunteer firefighter stuck in tree in Lefthand Canyon since 5AM just rescued. Serious injuries …
Link
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12z euro has trended a bit northward with 93L.. landfall is late Sunday into Monday morning
Member Since: May 30, 2013 Posts: 0 Comments: 564
Quoting 424. 69Viking:


You're way more on topic today than the GW alarmists are!


They think they own the blog. They call you "denialist", "uneducated", "ignorati". Over on another blog they posted a joke with pictures of monkeys suggesting that if you do not believe in GW that you are a monkey. Very sad.
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Boulder County Sheriff and Fire Live Audio Feed



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Quoting 430. FunnelVortex:


The Borg would say

"Where did this tin can come from?"

Another would answer...



Or maybe they'd say,
"There go those humans -- skipping 'stones' into space again."
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Quoting 413. FunnelVortex:


No waves? CV season is over...
There was a cape verde season?
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439. BA
Quoting 425. MississippiWx:


Yeah, it looks like it should basically stall for 2 or 3 days before making a move. The NAVGEM's solution would be best for Texas. However, it doesn't have much company with this track and, after all, it's the NAVGEM. Lol.



the reason I even comment when people say this thing needs to go to Texas they need rain or this is best for Texas is because I live on the Texas coast and those types of comments are mostly from people that don't live on the Texas coast, otherwise, they would know that a little storm can ramp up to complete devastation very quickly...basically, you don't want storms coming your way this time of year if you live on the Texas coast, period...once you've gone through a few you know that...you also know that we will get the rain in other ways
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Quoting 433. txjac:


I just dont see how that blob could meander for a couple of days ...there is so much land close to it


Most storms this season have been shoved into Mexico because of the strong "death ridge," that's been over the central United States. This ridge is retreating and breaking down, and it'll probably cause 93L to stall out and probably loop around close to the southern coast before being drawn north. Has about 4 days over water to strengthen. Situation is somewhat reminiscent of Hurricane Nate in 2011.
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Looks like the 12z ECMWF trended a bit north compare to the 0z run. Looks like landfall Sunday Evening/night between Tampico and Brownsville. The Euro is also faster with 93L nearing the coastline by a good 12 hours or so.
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Quoting 429. nrtiwlnvragn:


NASA Spacecraft Embarks on Historic Journey Into Interstellar Space

Excerpt:

"Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are."


Greatest milestone in human history since the Apollo 11 moon landing -- though you'll only see it on Fox News or CNN as a little tidbit article on the bottom of the science/technology page.
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I am tired of the BOC this year , no room on my tracking map , Barry , Fernand , TD 8 , Barbara , over the BOC , form somewhere else please! Maybe the middle of the GOM , I am over the 2013 Hurricane season ! Bring on 2014 season! I know it only takes one , but seriously this season is a farce , and it's not GW fault , this stinks , bring on a season like 2004 or 2005 ! This is a lousy tracking season , like they say on ESPN football show C'MON on man !
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#405... Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.

Please continue posting!!! Your updates are very relevant and informative. I am at work and the only way I can follow your current situation is from the posts.

Thanks!
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433. txjac
Quoting 419. CybrTeddy:
Impressive how quickly these BoC systems can wind up. I'm going to guess 35mph TD at 5pm, still looking rather blobby. Models are saying it'll meander in the BoC for a few days, perhaps looping around once before heading north under the influence of a breakdown in the ridge. If that's the case, a 65kt system isn't out of the question.


I just dont see how that blob could meander for a couple of days ...there is so much land close to it
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Quoting 414. NEFLWATCHING:

Sometimes the hardest thing to do is to sit on your hands and let the warring sides wear themselves down.


Maybe so, maybe so.
I do despise the petty politics that can be seen at times. Whether I agree with a person's ideology or philosophy, politics, etc....or not, I can still manage to reach & make a positive "plus"-click on a good post. Many cannot. They'd rather die, it seems, once they mark a person as "the enemy" in their petty minds. It is like school kids shunning another kid & perr-pressuring him/her out. Wow, yet I have seen kids be more mature. Hopefully this blog will improve in that aspect, as it has a lot going for it, otherwise.
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Quoting 425. MississippiWx:


Yeah, it looks like it should basically stall for 2 or 3 days before making a move. The NAVGEM's solution would be best for Texas. However, it doesn't have much company with this track and, after all, it's the NAVGEM. Lol.



Maybe, but the idea that it'll be stuck in the BoC is certainly supported by most of the models.*


*that don't suck, the BAMS members are shoving it into Mexico.
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Quoting 416. WalkingInTheSun:


Just Dandy!
Now the Borg will know where to find us!


The Borg would say

"Where did this tin can come from?"

Another would answer...

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Quoting 399. CybrTeddy:
Just a little OT topic here:

Voyager 1 has left the solar system!


NASA Spacecraft Embarks on Historic Journey Into Interstellar Space

Excerpt:

"Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are."
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Alarmists?

NASA?

climate.nasa.gov

Do you know where your blogging ?

Consensus: 97% of climate scientists agree

LOL
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Quoting 420. JLPR2:


Disturbance just off the coast of Africa has a weak circulation.



There is an interesting looking area in eastern Africa.


Good you posted a closeup view. Yes,interesting that one.
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Quoting 405. MrMixon:


Perhaps... but rain continues to fall. This might be predecessor to a larger slide. Numerous slides have been reported throughout the county. If I find a photo of a larger slide I'll post it for you, alright?




Small solace for the families of the three people who have died today and the numerous people who are still trapped in homes or vehicles.



Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.
Please keep posting regular updates as you can, and stay safe.
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Quoting 408. CybrTeddy:


Models say it'll loop around in the BoC behind the ridge and be forced northward, or at least the more reliable models are saying that.


Yeah, it looks like it should basically stall for 2 or 3 days before making a move. The NAVGEM's solution would be best for Texas. However, it doesn't have much company with this track and, after all, it's the NAVGEM. Lol.

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Quoting 405. MrMixon:


Perhaps... but rain continues to fall. This might be predecessor to a larger slide. Numerous slides have been reported throughout the county. If I find a photo of a larger slide I'll post it for you, alright?




Small solace for the families of the three people who have died today and the numerous people who are still trapped in homes or vehicles.



Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.


You're way more on topic today than the GW alarmists are!
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Quoting 394. clwstmchasr:


Clearly moving much faster than the models or NHC forecasted. I don't see anyway this gets up near Texas.

No it's not..moving as predicted.. it slow down as in the TWO
Member Since: May 30, 2013 Posts: 0 Comments: 564
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421. BA
Quoting 403. B183:

Take note that I said a strong tropical storm or Cat 1. Outhouses in Corpus are made to take that. I am well aware that the watershed for Corpus is inland, but these storms can't fill it without going over the coast first. Funny how that works.


yep
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420. JLPR2


Disturbance just off the coast of Africa has a weak circulation.

Quoting 409. Tropicsweatherpr:


It looks like no new well organized waves inside Africa.


There is an interesting looking area in eastern Africa.
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Impressive how quickly these BoC systems can wind up. I'm going to guess 35mph TD at 5pm, still looking rather blobby. Models are saying it'll meander in the BoC for a few days, perhaps looping around once before heading north under the influence of a breakdown in the ridge. If that's the case, a 65kt system isn't out of the question.
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418. yoboi
Quoting 395. Neapolitan:
Also "intentionally misrepresents". ;-)



-3
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Does water shortage prone Colorado have any hope of capturing a chunk of this runoff?
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Quoting 399. CybrTeddy:
Just a little OT topic here:

Voyager 1 has left the solar system!


Just Dandy!
Now the Borg will know where to find us!
Member Since: Posts: Comments:
Quoting 405. MrMixon:


Perhaps... but rain continues to fall. This might be predecessor to a larger slide. Numerous slides have been reported throughout the county. If I find a photo of a larger slide I'll post it for you, alright?




Small solace for the families of the three people who have died today and the numerous people who are still trapped in homes or vehicles.



Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.
They are very much on-topic here, especially given that, you know. Dr. Masters' current blog entry is headlined by the ongoing Colorado disaster. Please don't let the ignorati dissuade you from posting here.
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Quoting 362. WalkingInTheSun:


I agree, and this time I will try to not even make peace between the sides, lest I get accused or it be implied that I was doing anything bad. lol.

Sometimes the hardest thing to do is to sit on your hands and let the warring sides wear themselves down.
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Quoting 400. JLPR2:
And this is what a hurricane can do to an extensive area of dry air.



Of course this year's supply of SAL/Dry air is impressive and more is emerging from Africa.



No waves? CV season is over...
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Next 10 to 12 Days
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Quoting 405. MrMixon:


Perhaps... but rain continues to fall. This might be predecessor to a larger slide. Numerous slides have been reported throughout the county. If I find a photo of a larger slide I'll post it for you, alright?




Small solace for the families of the three people who have died today and the numerous people who are still trapped in homes or vehicles.



Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.


Definitely not bothering me. I'd love to continue hearing updates.
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Quoting 403. B183:

Take note that I said a strong tropical storm or Cat 1. Outhouses in Corpus are made to take that. I am well aware that the watershed for Corpus is inland, but these storms can't fill it without going over the coast first. Funny how that works.


Remember, you are talking about TX...in September.
It is not unfathomable that a Cat 1 hurr. could come up to CC, pass over, be met by a frontal system from the North, stack up T-storms & rain all over the state.
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Quoting 400. JLPR2:
And this is what a hurricane can do to an extensive area of dry air.



Of course this year's supply of SAL/Dry air is impressive and more is emerging from Africa.



It looks like no new well organized waves inside Africa.
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Quoting 352. MississippiWx:


If it is already that far into the Bay of Campeche, I don't see it moving much farther to the north. It has to start putting on the brakes, like now.


Models say it'll loop around in the BoC behind the ridge and be forced northward, or at least the more reliable models are saying that.
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406. yoboi
Quoting 372. Patrap:
That's what some can't grasp seems, there are no sides.


There's the data,the consensus and observed trends Globally

All else, is jus noise.


Fresca?


are we putting some EC in da fresca ???
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Quoting 341. seer2012:That really is a very minor slide for Co. mtn. roads!


Perhaps... but rain continues to fall. This might be predecessor to a larger slide. Numerous slides have been reported throughout the county. If I find a photo of a larger slide I'll post it for you, alright?


Quoting 323. WalkingInTheSun:


Not to knock CO, but that is simply a rain-swollen gully in some other places.


Small solace for the families of the three people who have died today and the numerous people who are still trapped in homes or vehicles.



Sorry, folks, if our disasters in Colorado aren't big enough for this blog. I thought my updates were on topic, but I'll discontinue them if I am bothering people. Check my blog for additional updates.
Member Since: March 26, 2006 Posts: 44 Comments: 1520
Quoting 385. FunnelVortex:


I guess they finally got enough funding. lol


Sequester is not over yet, so maybe Putin felt sorry for the USA and loaned us the $$$. Heh.
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403. B183
Quoting 364. BA:


no windstorm insurance? it is required by law...and obviously the comment about CC will gladly eat a storm like "Ingrid to be" to fill the lake levels...no, first off, our water shed is far inland, second, in order to get such a thing it would wipe us out on the island

Take note that I said a strong tropical storm or Cat 1. Outhouses in Corpus are made to take that. I am well aware that the watershed for Corpus is inland, but these storms can't fill it without going over the coast first. Funny how that works.
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Boulder's 9news.com has a live feed on their website.
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Quoting 388. SomeRandomTexan:
If 93L doesn't put on the brakes soon, it will never gain any latitude and will slam into Mexico soon. She is running out of real estate and needs to really slow down.
I agree. This thing looks like it won't get above 22N imo.
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400. JLPR2
And this is what a hurricane can do to an extensive area of dry air.



Of course this year's supply of SAL/Dry air is impressive and more is emerging from Africa.

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Just a little OT topic here:

Voyager 1 has left the solar system!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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