Egypt3 Flash Flood Event

[brian_noaaguy]

Hello Everyone,

I've put together an analysis of the Egypt3 Slot Canyon flash flood event that resulted in two fatalities on September 10th. I

f you don't remember, I'm a Hydrologist with the National Weather Service in Salt Lake City, and the guy who oversees our flash flood program for Utah. I have been a part of Bogley for some time, and have been a professional ski patrolman, canoe guide, and raft guide in my former life. I gain lots from this community with regard to the National Weather Services flash flood program.

I've put the analysis in two forms. The first is a powerpoint presentation. The second is essentially the same presentation, but with my voice accompanied with the slides.

You can find the analysis at:

http://www.wrh.noaa.gov/slc/river/presentations/

I welcome any comments you may have. Thanks again.

Brian.

[skianddive]

I welcome any comments you may have. Thanks again.
Great stuff, Brian. The presentation should be required reading for any canyoneer attempting a canyon when conditions are threatening or when there is any possibility of rain within a canyon's watershed.

The amount of rain in the Egypt-3 area that day (i.e. 3/10 of an inch) was minuscule as defined by established standards, especially here in SoCal. But the affect in the canyon - that is, peak flow at 450cfs and probable depth of 20' - is mind boggling.

On Slide #13, you mention that the "actual calculation and analysis methods are available" for how you determined the above stats. Are they available on-line or in a spreadsheet?

Thanks for your work!

[brian_noaaguy]

Thanks for the kind words. That was my mostly my goal. To illustrate how little rainfall caused such a tragic event.

I have the methods and equations used in a microsoft word document. I had worked with another hydrologist named Ed Clark, from the Colorado River Basin Forecast Center. He is also an outdoor guy and fellow hydrologist.

I will attach the file here.

Brian.

[Scott Card]

WOW! Very nice work. One question is what width did you calculate the canyon to be? Another question is where in the canyon did you have th 20' depth? Beginning? Middle or End or all of the above. Again, thanks for the great info and description. That 20' depth is what blew me away. I figured 5-6 feet max using absolutely no science or math :haha:

[brian_noaaguy]

We tried to calculate the volume of water moving through an opening that narrow. My feeling is that the height of the water was lower in wider areas, but as this slot is extremely narrow in most places, 20 ft. seemed accurate.

[Jaxx]

very cool report. That is so crazy that .3" in 1.2 miles squared made a flash in the slot 20 ft deep!!! I am going to take the moderate flash flood warnings more seriously now. Thanks for putting that together and posting it here.

[Scott Card]

Hey Brian, are you going to post this over on the Yahoo Group? I know many on the group would appreciate it. If not, may I cut and paste it over there for them to see (all the credit to you of course)?

[brian_noaaguy]

Thanks. We thought the same. This is probably happening much more in this area.

[brian_noaaguy]

Scott,

I would think it we could share this with as many people possible, all the better.

Brian.

[Brian in SLC]

I would think it we could share this with as many people possible, all the better

Great analysis. Really highlights the risk well. That amount of rainfall occurs at that location at least once a year. Wow. Not an "unusual" event at all. In fact, quite common.

The rating thing is the same thing we in the ski world get frustrated at too. "Moderate" hazard. If the kids (and grizzles old timers too!) these days (and, ahem, guides) don't hear the word "EXTREME" then folks tend to blow it off as ok and/or safe. For avalanches, "moderate" means possible.

"Moderate - Localized slot canyons, dry washes, and small streams may experience flash flooding."

Sometimes its hard to be conservative. Toss in group think, or, other agendas, and you blur that judgement pretty quickly.

Good food for thought.

Great stuff, thanks!

-Brian in SLC

[trackrunner]

Hey Brian, are you going to post this over on the Yahoo Group? I know many on the group would appreciate it. If not, may I cut and paste it over there for them to see (all the credit to you of course)?

It has already been posted before in the yahoo groups

Saw it a couple weeks ago

[Scott Card]

How'd I miss that? Thanks for the heads up.

[Mtnman1830]

Really is amazing stuff. Thanks for sharing the info!

[CarpeyBiggs]

Hey Brian, are you going to post this over on the Yahoo Group? I know many on the group would appreciate it. If not, may I cut and paste it over there for them to see (all the credit to you of course)?

It has already been posted before in the yahoo groups

Saw it a couple weeks ago

Not the link with Brian's voice, or the data sheet on how it was computed. Bruce posted it on Yahoo awhile back, but it could use another bump I think.

[Felicia]

Absolutely fabulous presentation! :hail2thechief: :hail2thechief:

Thank you for sharing. Awesome! :2thumbs:

[brian_noaaguy]

Thanks again. I liked the three guys. Nice touch. Really though, glad you like the analysis.

[stefan]

never mind ... got it working will listen to it this evening.

many thanks, brian, for posting this. it's an impressive medium to give slideshow talks via the web.

[stefan]

hi brian,

so i understand a little about what my problem was with loading the new page, and i am not sure if this is an issue that's isolated to mac/OSX or if it's also the case with windows as well.

i was able to determine using two different (mac) computers, that the latest version of adobe flash seems to cause problems with your software, resulting in the slideshow not loading and the whole page breaking.

from logs i can't really tell what's the difference between the two.

[brian_noaaguy]

Stefan,

The presentation should load on both mac and pc. I've got a mac, but tested it on a pc before sending out the link.

What happened when you tried to open it the first time?

[brian_noaaguy]

Stefan,

After looking around, I came across a bit of information that illustrated a problem with Adobe Flash Player v. 10 which causes webcasts using Articulate Presenter to fail on load.

Could this be what's messing with your system?

[stefan]

yes, that would be consistent with what i was saying.

the only difference i found between the two computers was that the one that had the older version of adobe flash worked whereas the one with the latest version of flash didn't work. i additionally had a friend who didn't update test it out. it worked for him with an older version of flash, and then the slideshow failed to load once he updated to the latest flash.

it's unfortunately that this update causes this problem.

[skianddive]

From http://www.articulate.com/support/kb/002567.php (http://www.articulate.com/support/kb/002567.php)

Why are my presentations not loading with Flash Player 10?

If you've published presentations with Articulate Presenter 5, they may not load when viewed with Flash Player 10.

To fix this problem, download and use the Articulate Updater for Adobe Flash Player 10 (http://www.articulate.com/downloads/full/presenter/flash10-updater/f10updater.exe).

[stefan]

thanks, lee, for finding the update.

from first glance and cursory search it looks like they only have an update for windows (.exe), although they do reference mac at the bottom of the page. i'll have to look more closely at this later.