yosemite to flood??

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Clint Cummins

Trad climber
SF Bay area, CA
Jan 5, 2017 - 08:12pm PT
Current forecast is 15.9 feet at 4pm Sunday.
http://water.weather.gov/ahps2/hydrograph.php?wfo=hnx&gage=pohc1
Not as bad as 23.1, but since:
 11.5 sewage pumping relay station at North Pines floods
 12.5 both Northside Drive and Southside Drive close
it could still be a pretty big disaster.
Maybe since the sewage infrastructure was repaired after 1/1997,
it will hold up better this time, but bad things can happen when there's a lot of water hammering things.
EdBannister

Mountain climber
13,000 feet
Jan 5, 2017 - 09:41pm PT
Gee current forecast is 15.9,

will anyone admit that this might mean the earlier forecasts, and the models were wrong?

When the forecasts were 23.1 and 23.7 i looked at the maps, and said my personal guess was under 17.

hmmmmmmm
Ken M

Mountain climber
Los Angeles, Ca
Jan 5, 2017 - 09:46pm PT
No, Ed, the earlier was not wrong.

BECAUSE IT HASN'T HAPPENED YET.

It might be exactly right.

These are only predictions, which become more likely accurate the closer we get.

But we don't know TRUTH until it happens.
EdBannister

Mountain climber
13,000 feet
Jan 5, 2017 - 09:49pm PT
Valid point Ken! if i had stated it absolutely,

you might want to reread

i wrote might mean, because it has not happened yet.

but you will be the first to say the models are not worth the time to look at them when it is under 17 feet, right?
or you might even apologize for yelling with caps when you had not read what i wrote.

Reilly

Mountain climber
The Other Monrovia- CA
Jan 5, 2017 - 10:15pm PT
this might mean the earlier forecasts, and the models were wrong?

More likely is that they're backing off so as to not look so foolish
claiming the sky is falling.

Regarding the sewage pumps, did they not learn anything in '97?
Did they not think it could happen again? I know it isn't their money
but isn't insanity the repetition of doing the same thing wrong?
Clint Cummins

Trad climber
SF Bay area, CA
Jan 5, 2017 - 11:11pm PT
In my view, the "model" is a series of calculations that starts with input data on current temperatures and pressures at multiple locations over the Pacific Ocean over time,
plus current snowpack estimates and computes a forecast at this particular bridge at time points in the future.

What the model does is predict temperature and precipitation amounts over the watershed area upstream from the bridge, and estimate how much snow will melt as well.
Then the model adds up the precip/melt at points on the grid and uses the distances and slopes to the bridge point to predict river height at each time point.
What has likely changed is the "input data", mostly the ocean temperatures and pressures.

Sophisticated predictions will also show a range of likely outcomes, which statisticians call a "confidence interval".
In this particular plot, we just see the point forecasts and not a range.
But it's likely that the range is output by the model and is just not shown on this plot.

I'm also not sure what "wrong" means.
It seems like 15.5, 15.9, 17, 23.1, etc. are all way bigger than 11.5 and 12.5,
so the prediction has been steady that this is likely to be a big event with damage and closures.
However, I don't know how damage might scale nonlinearly with the actual depth.
healyje

Trad climber
Portland, Oregon
Jan 6, 2017 - 12:41am PT
My guess is it's fairly dependent on how steady the jetstream speed and location hold. If it holds at a 140 over the Sierras then it's a good bet, if it weakens, wobbles or shifts then that will throw a wrench in the forecasts. Looking fairly solid at the moment and given the midwest forecasts call for the entrenching of the arctic air mass (polar vortex) over the northern half of the country I don't expect the jetstream to be changing much.





Ed Hartouni

Trad climber
Livermore, CA
Jan 6, 2017 - 01:32am PT
here's the historic record of the Pohono Bridge flow gauge going back to 1917

Reilly

Mountain climber
The Other Monrovia- CA
Jan 6, 2017 - 07:56am PT
The ol' Polar Vortex is another concoction of the effete elitist news media selling ad time.
It hasn't been below -20F in Fairbanks yet this winter. That's like spring up there.
WBraun

climber
Jan 6, 2017 - 08:04am PT
If the river goes to 12 the Valley can handle it as I've seen both times when it went that high.

El Cap bridge usually gets a heavy log jam there.

Devils elbow goes under water all the way to end of Elcap straight.

Chapel straight goes under water.

But 20 feet will be very very bad because it can take out the road/s in various places.



Ed Hartouni

Trad climber
Livermore, CA
Jan 6, 2017 - 09:50am PT

The ol' Polar Vortex is another concoction of the effete elitist news media selling ad time.
It hasn't been below -20F in Fairbanks yet this winter. That's like spring up there.

one is startled at the incredible stupidity of this remark, but apparently looking at the maps that healyje quoted above, and knowing where Fairbanks Alaska is on those maps, with respect to the jet stream configuration, apparently doesn't evoke any challenge to the emerging ipse dixit brigade on the STForum...

one is left to wonder just why we would expect any temperature anywhere to be different from what our notion of what that temperature should be...

the failure of logic is jaw dropping.

rottingjohnny

Sport climber
Sands Motel , Las Vegas
Jan 6, 2017 - 09:58am PT
Reilly calls em as he sees them... minus 20 but feels like minus 35...
Srbphoto

climber
Kennewick wa
Jan 6, 2017 - 10:02am PT
The ol' Polar Vortex is another concoction of the effete elitist news media selling ad time.
It hasn't been below -20F in Fairbanks yet this winter. That's like spring up there.

but it did hit =20 this morning in Baker City, OR
Prod

Trad climber
Jan 6, 2017 - 10:21am PT
one is startled at the incredible stupidity of this remark, but apparently looking at the maps that healyje quoted above, and knowing where Fairbanks Alaska is on those maps, with respect to the jet stream configuration, apparently doesn't evoke any challenge to the emerging ipse dixit brigade on the STForum...

one is left to wonder just why we would expect any temperature anywhere to be different from what our notion of what that temperature should be...

the failure of logic is jaw dropping.

Gotta love an Ed H smack down....

Prod.
healyje

Trad climber
Portland, Oregon
Jan 6, 2017 - 11:47am PT
The ol' Polar Vortex is another concoction of the effete elitist news media selling ad time.

You've obviously never lived in Chicago.
healyje

Trad climber
Portland, Oregon
Jan 6, 2017 - 12:28pm PT
It wasn't predicted because the idea of atmospheric rivers was still fairly new and the '97 storm probably woke everyone up to their potential...

The term atmospheric river was coined in a seminal scientific paper published in 1998 by researchers Zhu and Newell at MIT

An ARKStorm (for Atmospheric River 1000 Storm) is a hypothetical but scientifically realistic "megastorm" scenario developed and published by the United States Geological Survey, Multi Hazards Demonstration Project (MHDP).

kunlun_shan

Mountain climber
SF, CA
Jan 6, 2017 - 01:53pm PT
Apparently the Valley is closing at 5pm today, through at least Sunday.

http://www.sfgate.com/bayarea/article/Yosemite-Valley-to-close-in-advance-of-menacing-10840593.php

EdBannister

Mountain climber
13,000 feet
Jan 7, 2017 - 10:06am PT
Matt, did they revise it down to 10 feet yet?
John M

climber
Jan 7, 2017 - 10:19am PT
No need to be snarky Ed. You have to forgive Ken. He is dealing with some rather serious health issues. He hasn't said what exactly, but he did say he was having difficulties walking.

Latest river estimate is 17.2 feet. As of 10:15 AM Sat.

The progression.

23.4
15.2
16.1
17.6

Its all a matter of how this storm lines up.
EdBannister

Mountain climber
13,000 feet
Jan 7, 2017 - 11:34am PT
looking at the weather maps and radar,

There is a strong stable front...

but i still do not see enough moisture in the system to agree with models that still say 17.. ok.. the Park is closed, liability lawyers appeased.

we will see.

Sunday 5pm is the predicted crest..

here is the USGS interactive Pohono Bridge Gaging Station link:
https://waterdata.usgs.gov/ca/nwis/uv?11266500
Messages 21 - 40 of total 202 in this topic << First  |  < Previous  |  Show All  |  Next >  |  Last >>
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