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News Monsoon is Here.

Discussion in 'General Discussion' started by Bootboy, Jul 11, 2018.

  1. Bootboy

    Bootboy Atwood Gear

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  2. ratagonia

    ratagonia

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  3. Bootboy

    Bootboy Atwood Gear

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    Virgin river just peaked over 5000 CFS! Larger than anything in nearly a decade.

    Wow!

    Over 2 inches of rain in less than 4 hours.
    Last edited: Jul 12, 2018
  4. ratagonia

    ratagonia

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  5. Bootboy

    Bootboy Atwood Gear

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    Last night’s flood event saw the seventh highest recorded stream flow in 105 years. Looks like the flow peaked at 5410. Could have been higher since measurements are taken at 15 minute intervals.

    The Virgin River at springdale has only crested 5000cfs 8 times in 105 years. And one of those was last night.


    That’s incredible.

    [​IMG][​IMG]

    A flood event like this is the type of flood that can seriously rearrange things in the canyon.

    I suggest anyone going into any Zion canyons be prepared for dramatically different conditions and take enough webbing to re rig every anchor in that canyon.
    Last edited: Jul 12, 2018
  6. hank moon

    hank moon lovely ligatures

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    The sky show last night was a-mazing!
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  7. hank moon

    hank moon lovely ligatures

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    Attached Files:

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  8. hank moon

    hank moon lovely ligatures

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  9. cboswel1

    cboswel1

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    Waited at the D Dam for an hour in hopes of catching it. Lucked out. Warning: Language

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  10. Kuenn

    Kuenn

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    That's a big time event, even for outside the west!

    The road closing announcement canyon junction to east entrance - indefinitely. Last time I recall that word used was the tunnel collapse. Going to put a hurt on folks that live out that way...

    @ratagonia I know a place where you might get your hands on some needed signage.
    IMG_0647.JPG
    darhawk, ratagonia and Rapterman like this.
  11. Rapterman

    Rapterman

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    WOW
    Monsoon is here with a boom and it's time for a NEW season of......
    CANYON ROULETTE! :wavespin:

    Let's see, 20% chance of rain = 20% of the coverage area WILL get rain =
    ONE live round in a FIVE shot revolver...

    Who wants to play?! :woot:
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  12. Muad'Dib

    Muad'Dib

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    I make an annual trip to Zion the first week of July to call down the monsoon season (“for he is the Kwisatz Haderach!”). I was there last week and I apologize if the prophecy was fulfilled in too great a measure this year.

    Perhaps now is a great time for a second edition from Tom:

    Zion: Canyoneering, The Post July 2018 Flood Edition


    Sent from my iPhone using Tapatalk
  13. Chasetharp

    Chasetharp

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    Seeing Rapterman's comment of things that I have heard before, I really feel a need to learn more about monsoon season.
    Any solid info out there that someone could share a link of? Or just good tips on how to keep yourself out of harm's way this time of year?
  14. ratagonia

    ratagonia

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    Not sure how this myth got started, but NO, that is not what 20% chance of rain means.
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  15. ratagonia

    ratagonia

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    Rule 1 for Monsoon season: The Forecast is a guess. Don't take it too seriously.

    - the last couple of years, in monsoon season, the forecast has been unuseful. The forecast says 80% chance, no rain. The forecast says 20% chance, rained cat and dogs. The exact results of a monsoon day are very hard to predict. They do their best, but their best is not all that good.
    - one way you can see this is that the forecast moves around a lot. Trying for a canyon on Saturday, say, the forecast will look good on Tuesday, not so good on Wednesday, terrible on Thursday, then it will rain on Friday and clear off for Saturday.

    Rule 2 adapted from small plane piloting: It is better to be at home wishing you were in a canyon, then in a canyon wishing you were home.

    Tom
  16. gajslk

    gajslk

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    Kinda sounds like ... ONE live round in a FIVE shot revolver... :)
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  17. Rapterman

    Rapterman

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    ^^^^
    What he said :D
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  18. Brian in SLC

    Brian in SLC Brian in SLC

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    Per the example below, if the forecaster was 100% sure that 20% of the forecast area would see rain...then...the PoP is 20%.

    But, yeah, it doesn't usually mean that.

    https://www.weather.gov/ffc/pop

    Explaining "Probability of Precipitation"

    Forecasts issued by the National Weather Service routinely include a "PoP" (probability of precipitation) statement, which is often expressed as the "chance of rain" or "chance of precipitation".

    EXAMPLE
    ZONE FORECASTS FOR NORTH AND CENTRAL GEORGIA
    NATIONAL WEATHER SERVICE PEACHTREE CITY GA
    119 PM EDT THU MAY 8 2008

    GAZ021-022-032034-044046-055-057-090815-
    CHEROKEE-CLAYTON-COBB-DEKALB-FORSYTH-GWINNETT-HENRY-NORTH FULTON-
    ROCKDALE-SOUTH FULTON-
    INCLUDING THE CITIES OF...ATLANTA...CONYERS...DECATUR...
    EAST POINT...LAWRENCEVILLE...MARIETTA
    119 PM EDT THU MAY x 2008

    .THIS AFTERNOON...MOSTLY CLOUDY WITH A 40 PERCENT CHANCE OF
    SHOWERS AND THUNDERSTORMS. WINDY. HIGHS IN THE LOWER 80S. NEAR
    STEADY TEMPERATURE IN THE LOWER 80S. SOUTH WINDS 15 TO 25 MPH.
    .TONIGHT...MOSTLY CLOUDY WITH A CHANCE OF SHOWERS AND
    THUNDERSTORMS IN THE EVENING...THEN A SLIGHT CHANCE OF SHOWERS
    AND THUNDERSTORMS AFTER MIDNIGHT. LOWS IN THE MID 60S. SOUTHWEST
    WINDS 5 TO 15 MPH. CHANCE OF RAIN 40 PERCENT.

    What does this "40 percent" mean? ...will it rain 40 percent of of the time? ...will it rain over 40 percent of the area?

    The "Probability of Precipitation" (PoP) describes the chance of precipitation occurring at any point you select in the area.
    How do forecasters arrive at this value?

    Mathematically, PoP is defined as follows:

    PoP = C x A where "C" = the confidence that precipitation will occur somewhere in the forecast area, and where "A" = the percent of the area that will receive measureable precipitation, if it occurs at all.


    So... in the case of the forecast above, if the forecaster knows precipitation is sure to occur ( confidence is 100% ), he/she is expressing how much of the area will receive measurable rain. ( PoP = "C" x "A" or "1" times ".4" which equals .4 or 40%.)

    But, most of the time, the forecaster is expressing a combination of degree of confidence and areal coverage. If the forecaster is only 50% sure that precipitation will occur, and expects that, if it does occur, it will produce measurable rain over about 80 percent of the area, the PoP (chance of rain) is 40%. ( PoP = .5 x .8 which equals .4 or 40%. )

    In either event, the correct way to interpret the forecast is: there is a 40 percent chance that rain will occur at any given point in the area.
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  19. Canyonero

    Canyonero

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    Shoot. I'm taking some youth this week down a few canyons. That's a lot of webbing! Hopefully some of it is still good. Should be dramatically different than the conditions when I did the same canyons a month ago. That's okay, I prefer them wet (except Birch Hollow.)
  20. Canyonero

    Canyonero

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    If anyone goes down the 4x4 road to Orderville since this rain, I would really appreciate an update on condition.
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