Observations: Spencer's Creek Snowdepth 2017

Discussion in 'Weather' started by Miffy, Jun 8, 2017.

  1. jonathanc

    jonathanc Dedicated Member

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    My reasoning for the 178cm guess was a 6:1 precip ratio (rather than the 10:1 in some of the charts posted) and then took off a bit for compaction.
     
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  2. Red_switch

    Red_switch Part of the Furniture
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    A 6:1 precip ratio is 16% SWE density, which is probably pretty reasonable - off the top of my head that's probably around the lowest density I've measured for recent storm snow in a snow pit in NZ. 1:10 is the holy grail around here, and rarely seen.

    It usually doesn't take long for settled snow to reach a density around 30% around here (NZ), and unless you get decent facet growth it'll stay around there until it goes isothermic in spring.
     
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  3. Rabid K9

    Rabid K9 Dedicated Member
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    Off the top of your head RS, what are some are of the other densities you've seen / know of in other area countries (i.e.: Honshu, / Hokkaido, Austria / Italy, US etc)?
     
  4. Red_switch

    Red_switch Part of the Furniture
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    Occasionally read numbers of 6-8%, although that seems to mostly appear in older literature...
     
  5. Snow Blowey

    Snow Blowey Part of the Furniture
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    I don't see how CP ever does not get as much snow as Perisher and Thredbo. It is smack in the middle of the two, up on the same plateau as Perisher - only closer to the main range. The slope that the measuring locations are on would never get less snow than Perisher from a classic NW and W dump.

    I think Perisher and Thredbo just did a bit of double accounting for the social media beat up.
     
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  6. BlueHue

    BlueHue Dedicated Member

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    Alta report density in snowfall statistics. 6-8% seemed pretty standard for winter months, anything above 10% was unusual and the odd storm provided densities under 5%:

    http://www.alta.com/conditions/weather-observations/snowfall-history
     
    #206 BlueHue, Aug 11, 2017
    Last edited: Aug 11, 2017
  7. BlueHue

    BlueHue Dedicated Member

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    When estimating SC depths I take reported snowfall totals from Thredbo, Perisher and CP. If they are close I use an average, if there are outliers I usually default to CP. I then take 60-70% of the total accumulated snow for the week to allow for depth of snow once settled and add to previous weeks reading (unless the snow was unusually dry in which case I allow closer to 50% for settled snow depth and ~80% if the snow was water filled stodge). If there's no significant warmth or wet for the week that's my guess. If there has been significant loss I stab myself, read the patterns in the blood and take a wild guess at how much loss before adjusting my guess for SC snow depth.
     
  8. Hemsley

    Hemsley Dedicated Member

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    All things being equal it seems like a very good season, across the board . Yes the bigger resorts talk themselves up , however there has been good snow fall, with more to come. Hopefully next week we crack the 2m mark. Anyway I'm going to the pub.
     
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  9. Red_switch

    Red_switch Part of the Furniture
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    Utah is particularly anomalous globally when it comes to particularly low density snow.
     
  10. Lady Penelope

    Lady Penelope Dedicated Member
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    2 metres? Ambitious! Given the significant clear precipitation likely on Tuesday and Wednesday I am sadly predicting a loss.
     
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  11. coops

    coops Active Member

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    Telestrom Addicted Member

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  13. Lady Penelope

    Lady Penelope Dedicated Member
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  14. rocketboy

    rocketboy Dedicated Member
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    Neither of those linked reports explained much at all about the actual process of measuring the snow depth. There was a shot of the core being weighed. But no subsequent explanation of how the equation is constructed used to arrive at a final number.
     
  15. MarkV

    MarkV Active Member
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    Perisher Valley Forecast
    No warnings for New South Wales

    Forecast issued at 4:45 am EST on Sunday 13 August 2017.

    Forecast for the rest of Sunday
    Summary
    [​IMG]
    Max 4
    Possible morning snow shower.
    Possible rainfall: 1 to 2 mm
    Chance of any rain: 40% [​IMG]
    Alpine area
    Partly cloudy. Medium (40%) chance of snow showers this morning. Winds west to northwesterly 30 to 45 km/h tending northwesterly in the late evening.

    Sun protection recommended from 10:50 am to 1:50 pm, UV Index predicted to reach 3 [Moderate]

    7 day Town Forecasts
    Precis Icon Location Min Max
    [​IMG] Thredbo Top Station – 2
    [​IMG] Perisher Valley – 4
    Monday 14 August
    Summary
    [​IMG]
    Min -2
    Max 8
    Partly cloudy.
    Possible rainfall: 0 to 0.4 mm
    Chance of any rain: 20% [​IMG]
    Alpine area
    Partly cloudy. Slight (20%) chance of light rain. Snow possible above 1900 metres. Winds west to northwesterly 35 to 50 km/h decreasing to 25 to 35 km/h in the evening.

    Sun protection recommended from 10:50 am to 1:50 pm, UV Index predicted to reach 3 [Moderate]

    Tuesday 15 August
    Summary
    [​IMG]
    Min -2
    Max 6
    Rain. Windy.
    Possible rainfall: 5 to 15 mm
    Chance of any rain: 80% [​IMG]
    Alpine area
    Cloudy. High (80%) chance of rain in the afternoon and evening. Winds westerly 20 to 30 km/h turning northwesterly 35 to 55 km/h during the morning then increasing to 40 to 60 km/h during the afternoon.

    Sun protection recommended from 10:40 am to 2:00 pm, UV Index predicted to reach 4 [Moderate]

    Wednesday 16 August
    Summary
    [​IMG]
    Min 0
    Max 3
    Snow at times. Windy.
    Possible rainfall: 8 to 15 mm
    Chance of any rain: 70% [​IMG]
    Alpine area
    Cloudy. High (70%) chance of snow, most likely in the morning. Winds northwesterly 35 to 55 km/h.

    Sun protection recommended from 10:40 am to 2:00 pm, UV Index predicted to reach 4 [Moderate]

    Thursday 17 August
    Summary
    [​IMG]
    Min -1
    Max 1
    Snow showers.
    Possible rainfall: 8 to 15 mm
    Chance of any rain: 95% [​IMG]
    Alpine area
    Cloudy. Very high (95%) chance of snow showers. Winds northwesterly 30 to 40 km/h decreasing to 20 to 30 km/h during the morning.


    A bit of loss, followed by a bit of gain. Maybe about the same figure as last week?
     
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  16. Red_switch

    Red_switch Part of the Furniture
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    With a Mt Rose sampler the depth doesn't really matter. What the hydrologists are interested in is SWE, snow water equivalent, which that instrument measures directly. But it does have a depth scale on the side for reference.

    Presumably they have some snowboards throughout their snowcourse? Back calculating snow depth from SWE would raise a few eyebrows...

    Also, that weatherzone video shows one of the major problems for using those samplers in "warm" snowpacks.
     
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  17. Snow Blowey

    Snow Blowey Part of the Furniture
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    Pretty sure its just an average of a number of readings. 10 snow poles. Take the average. Irons out local variations due to drifting snow.
     
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  18. rocketboy

    rocketboy Dedicated Member
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  19. Red_switch

    Red_switch Part of the Furniture
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    I'm yet to achieve a satisfactory calibration between a mt rose sampler and bulk density measured from a snow pit. In NZ it's so common to end up with vegetation/soil in the bottom of the core, ****s the density measurement right up.
     
  20. Red_switch

    Red_switch Part of the Furniture
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    10 is probably nowhere near enough to account for spatial variability. But it is a very difficult thing to achieve from in situ measurements.
     
  21. Scoober

    Scoober Active Member

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    Going for minimal loss for next reading 162.5
     
  22. Lady Penelope

    Lady Penelope Dedicated Member
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    167 Jellybeans in the jar for me...
     
  23. Bato

    Bato Dedicated Member
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    I think we will be close to break even, would have been snowing at 1850m for quite a while before it got down to 1700.
     
  24. Adelaidometer

    Adelaidometer Active Member

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    nickxylophone New Member

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  26. IAB

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  27. Hemsley

    Hemsley Dedicated Member

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    Despite what happen earlier in the week I'm still going 2 metres.
    200.00

    ......all depends on what time of the day the reading is done (changing hour by hour,this week).
     
    #227 Hemsley, Aug 17, 2017 at 5:57 AM
    Last edited: Aug 17, 2017 at 6:14 AM
  28. Bato

    Bato Dedicated Member
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    168.3, they took the reading on the 15th.
     
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  29. Adelaidometer

    Adelaidometer Active Member

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    Or some folk would say *163.8
     
  30. Lady Penelope

    Lady Penelope Dedicated Member
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    Yes, 163.8 it is as at 15/8. I guess they didn't fancy a trip out in the blizzard today! @Scoober is this week's winner ...
     
  31. Bato

    Bato Dedicated Member
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    Correct, im positive im becoming dyslexic!
     
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  32. FourSquare04

    FourSquare04 Dedicated Member

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    Should be interesting to see what it reads next week

    Definitely a net gain IMO around the 2m mark is looking likely at this rate
     
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  33. Hemsley

    Hemsley Dedicated Member

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    What! did a reading on the Tuesday? what pussies. it was only about a 100k wind.
    Well done Scoober.

     
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  34. sbm

    sbm Dedicated Member
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    @Red_switch @BlueHue Bruce Tremper the avalanche forecaster had a story about the lowest density snow he'd ever seen, in Montana, serious cold smoke which must have been about 5% but I don't remember the figures he quoted.

    They got several feet of it, sounds epic but it was so low density it offered zero resistance or floatation and your skis were clattering along the icy crust underneath the whole time!
     
  35. Red_switch

    Red_switch Part of the Furniture
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    I'd believe that!
     
  36. milesofmars

    milesofmars Active Member

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    As they are looking at water content my guess would be they did the reading on tuesday so they had a pre-rain estimate, so they knew what they were in for into there dams.

    plus if they are hydrologists doing it maybe preoccupied with the rivers today?
     
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  37. Roarkie

    Roarkie Active Member

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    IMO 198cm next Thursday (or whenever next week).
     
  38. Kopite

    Kopite Just Registered

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    I'll pitch in at 203cm
     
  39. IAB

    IAB Addicted Member
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  40. Taipan

    Taipan Part of the Furniture
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    240cm.

    It looked to have come from 179cm back about 10cm = 170cm approx + 80cm reported by Perisher over recent days = 250

    So Yeah say 240cm with a bit of natural compaction
     
  41. SMSkier

    SMSkier Dedicated Member

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    Seafm Dedicated Member
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  44. Scoober

    Scoober Active Member

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    nickxylophone New Member

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  46. Miffy

    Miffy Active Member

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    Hard to call before Monday's system, as much as I'd love to see another 2m season I just don't think it's there.
    That 163cm reading was taken on Tuesday 15th, before the deluge :(
    So 163cm minus 100+mm, IMO brings it back to about 120/130ish.
    Add "80cm" from Blizzard of Oz 2.0, and mayyyybe 5 cents from Monday's system minus four or five days of compaction
    =
    IMO 196cm :headbang:
     
  47. robbo mcs

    robbo mcs Dedicated Member
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    The tail end of the deluge fell as snow at 1850m, and the damage from the rain was not huge.

    The big unknown is the effect of windblown and drifting on the spencers reading. There are are some very big areas of snow accumulation around the eyre area of Mt P due to wind effect, the like of which we have not seen for years. I am not going to hazard a guess, but think we are at least 30cm higher than the previous peak at 179cm, so should be over 2m
     
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  48. whether

    whether Active Member

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  49. Adelaidometer

    Adelaidometer Active Member

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    So 163 would've been compacted down quite tight. The 100mm of rain after that would've bounced off, but caused a little melt. I reckon 20cm lost. Perisher said 70-80cm since 1830m asl being more like 80-90cm gain bringing it up to about 220 plus I guess another 5cm Monday. Temperatures remaining below zero until Thurs. Natural compaction without rain, skiers, without above zero temps and without groomers. Maybe a little windblown.

    My guess this far out: 223cm
     
  50. Lady Penelope

    Lady Penelope Dedicated Member
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    203cm for me - I will have to make some first hand observations at nearby Perisher this week :)
     
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