Mt Whitney Webcam
Mt Williamson Webcam
Feature Topics
Who's Online
1 registered (dbd), 12 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
3737 Members
10 Forums
5572 Topics
51016 Posts

Max Online: 382 @ 11/07/12 05:45 AM
Topic Options
#3776 - 04/26/10 10:22 PM Strange weather pattern for this spring
Ken Offline


Registered: 10/29/09
Posts: 742
Loc: Los Angeles
I have been quite purplexed by the weather pattern. When I look at the snow record:

snowpack

Look at the bottom chart, which runs from Isabella up to Tahoe, I think. What is remarkable is that the snowpack IS NOT MELTING! On April 1, the traditional end of the precip season, it was something like 105%. Each day, it is going up, BUT THERE IS NO MORE SNOW! What is happening is that the snow is remaining, but the historical level would be dropping. If you look at the last two years, and the rate of melting, if we were to experience that meltoff starting now, and it followed the same curve (which was fast), you would find that the place where the line intersects the bottom (no snow, on average), would be about a month later than the last two years.

In fact, during the next week, the temp is predicted to be higher than freezing ONCE. The HIGH on friday is predicted to be 17 degrees, and we may get more precip.

However, this pattern could continue for some time, and the curve could continue to shift. So we'd have this bizarre situation of a lot of snow late in the high country, but no more snow contributing to water storage. Very peculiar.

I also wonder about the contribution of the volcano. The ash it spewed out, micro particles, is the same sort of thing they use to seed clouds. Wonder if that will produce more rain when it gets around the world to us........

Top
#3781 - 04/26/10 10:47 PM Re: Strange weather pattern for this spring [Re: Ken]
Bee Offline


Registered: 09/22/09
Posts: 1261
Loc: Northern California
If I remember correctly, last year was strange in the fact that the EARLY part of the season was unseasonably warm (I remember skiing in shirtsleeves in Jan/Feb) While the late Spring & Summer was unseasonably cool (with the addition of a few snow storms in June), so we ended up with a slow melt in the highest Sierra elevations. If the snow persists at an even more exaggerated level this year, I may get my wish to ski Dana after Tioga opens.(providing that Tioga opens this year confused)
_________________________
The body betrays and the weather conspires, hopefully, not on the same day.

Top
#3783 - 04/26/10 10:57 PM Re: Strange weather pattern for this spring [Re: Bee]
Steve C Offline


Registered: 09/22/09
Posts: 7719
Loc: Fresno, CA
Yes -- slow melt last summer. I did my PCT section hike the end of June with way more snow than expected.

Ken, looking at the graph, this year's graph is following the 82-83 maximum graph -- later storms bringing the peak farther out.

I wouldn't try to overanalyze the short-term part of the graph, watching the line go up. But actually, when you think about it, the line CAN go up without any new snow. That is because it is tracking the percent of the average for a particular day. Any time we have cooler than average weather, less snow will melt than the average, so in comparison with the average, the percentage of average IS climbing. (Did I say that right?) Hope it makes sense.

In other words, even though snow is melting, and total water content is declining, if it melts slower than the average then the percent of average will increase.

Top
#3784 - 04/26/10 11:08 PM Re: Strange weather pattern for this spring [Re: Steve C]
Bee Offline


Registered: 09/22/09
Posts: 1261
Loc: Northern California
Originally Posted By: Steve C


In other words, even though snow is melting, and total water content is declining, if it melts slower than the average then the percent of average will increase.


There is a tidy mathamatical equation begging to bee expressed here....I am sure that some physicist could translate this clunky linguistic description quite handily whistle

_________________________
The body betrays and the weather conspires, hopefully, not on the same day.

Top
#3787 - 04/27/10 12:08 AM Re: Strange weather pattern for this spring [Re: Bee]
Steve C Offline


Registered: 09/22/09
Posts: 7719
Loc: Fresno, CA
Ha! In fact, there is something peculiar about graphing snow water content as a percentage of the average.

At some date in the summer, the average water content hits zero.

And in an above average water year, ANYTHING above zero water content after that point in time should approach infinity, since anything divided by zero is undefined.

Top
#3804 - 04/27/10 08:53 AM Re: Strange weather pattern for this spring [Re: Steve C]
Ken Offline


Registered: 10/29/09
Posts: 742
Loc: Los Angeles
Ah, the one additional thing is that the graph is of *april 1st* average, not simply average. On the graph, the april first average is, and always is, 100%. But the average for each day changes, and that average is only identical to the april first average once, on april 1.

So if the actual snowpack does not change, the percent of april 1 average does not change, either. However, the average for the date goes up every day. (currently 130%), which is tracked in the upper right corner of the graph. The daily average is tracked by the aqua area under the curve.

Top
#3808 - 04/27/10 09:20 AM Re: Strange weather pattern for this spring [Re: Ken]
Steve C Offline


Registered: 09/22/09
Posts: 7719
Loc: Fresno, CA
Ah, I missed that point -- it is the percent of the April 1 average. Kind of takes the wind out of all the points I was trying to make. blush

So maybe the graph's inching upward is more caused by the fact that it is an estimate. Nobody is going out and measuring water content at all those stations every day. All they have is those remote reporting stations, sending back signals of snow depth, so they can calculate water content. It isn't perfect science. ...so graphs may climb.

Top
#3810 - 04/27/10 09:43 AM Re: Strange weather pattern for this spring [Re: Ken]
CaT Offline


Registered: 09/24/09
Posts: 694
Loc: Blacklick, OH (formerly SoCal)
I believe we are in the second year of an El Nino, which tends to have two-year runs. This would explain the overall "late winter" aspects of what you are mentioning.

CaT
_________________________
If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)

Top
#3847 - 04/28/10 06:24 AM Re: Strange weather pattern for this spring [Re: CaT]
MooseTracks Offline


Registered: 11/02/09
Posts: 582
Loc: Bishop, CA, United States
Nino, Schmino... As long as I get a wicked spring skiing season that's all that matters to me... wink

Actually, I'll admit to being a little, well, ready for spring and the meltoff. There are some peaks deeper in that I want to climb!
_________________________
Facebook

Flickr Pics

Think outside the Zone.

Top