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Snow and Water levels 2011

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Snow and Water levels 2011

Postby kpeter » Wed Mar 30, 2011 10:26 pm

2011 is a very high snow year and this may substantially alter a lot of plans. Last year I periodically monitored 5 different automatic snow gauges at different elevations and posted the findings here to help people know how fast things were melting in different zones. The stations are chosen principally because they have the most reliable daily snow depth data that I could find at various elevations.

Here are the first readings, all as of 3/29/2011
Format = Station; Elevation; Snow Depth as of 3/29/2011; Snow Depth a year ago

Kibbie Ridge; 6700; 95.8; 39.9
Ostrander Lake; 8200; 156.1; 81.9
Slide Canyon; 9200; 147.6; 78.5
Charlotte Lake; 10400; 143; 72.9
Bishop Pass; 11200; 118.5; 65.5

As you can see, snow levels are pretty much double where they were last year in all five of these stations, and last year was an above-average year.

This does not necessarily mean a very late backpacking season, however. A lot will depend upon how warm May and June are.

What this emphatically WILL mean is dangerously high water levels in many streams during the melt, particularly if there is a hot spell. People should be EXTREMELY careful about early season trips. In fact, I would plan all trips during the melt to avoid crossings.

For example, last year in mid June the bridge at the outlet of Vernon Lake was surrounded by rapidly flowing water and a hiker was swept away just trying to reach that bridge. Imagine that situation this year with even more water going over for an even longer period of time.

There is a possibility that some bridges will be destroyed this year, so we will need to communicate with each other and the various authorities to know what to expect before our trips.
Last edited by kpeter on Thu Mar 31, 2011 8:58 am, edited 1 time in total.



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Re: Snow and Water levels 2011

Postby kpeter » Thu Mar 31, 2011 8:57 am

The most similar years (just above 150% water content) to 2011 are 1993 and 1998. The stations don't have raw snow depth that far back but they do have inches of water content. I took the Bishop Pass station to see if I could compare when the melt would be over and have concluded that it is equally dependent on how warm the spring is--meaning the speed of the melt--and not just the depth of snow.

Bishop Pass

(Year; peak inches of water content; final date of melt-out)

1993; 43.8; June 25
1998; 50.59; July 19
2011; 40.76 ???

2010; 31.69; June 30

1998 was extraordinary. It had quite a lot more snow (water content) than this year and its Spring must have been cool, with the melt-out not finishing at Bishop Pass until July 19. That is really late!

1993 in contrast has almost exactly the same amount of snow at this station as this year, and it melted out by June 25, which was five days earlier than last year's melt-out despite the fact that last year we had considerably less snow!

I'll check the gauges every couple of weeks (more often in May/June) to compare the rate at which things melt with 1993. That should give us a pretty good idea of when things will be opening.
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Re: Snow and Water levels 2011

Postby Jason » Thu Mar 31, 2011 9:05 am

Very cool. Thanks for doing the research.
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Re: Snow and Water levels 2011

Postby oldranger » Thu Mar 31, 2011 7:04 pm

Kpeter,

The new manual survey for Bishop Pass is 48+ inches of water which makes it very close to 1998.

As others have mentioned the amount of snow can make travel in the sierra interesting this summer. Most of us who are more experienced are well aware of the potential dangers. It has rightly been posted that once the snow has settled that travel over snow after it has softened a little in the AM can be relatively easy but the stream crossings can be treacherous. For those of you who have not experienced over snow travel please review the thread "Snow Travel for the inexperienced."

I want to add a couple of warnings that may have been stated on that thread but, even if they have, can stand to be repeated.

1. When traveling over snow in forested areas be alert for small, long, straight, rounded ridges in the snow. This can be an indication of a downed log underneath the snow. Frequently if you step just before or just after that ridge you will break through the snow. This is a potential leg breaker. I generally opt to take a long step directly on the ridge then a long step off.

2. Early in the morning or on cold days gray snow can be an indication of slippery ice.

3. If you are crossing a snow field and there is a rock sticking out of the snow treat it like # 1 or avoid altogether. Talus fields can be much easier to traverse when covered by snow but, nontheless there are risks!

4. If you are in a basin or canyon avoid the bottom and keep to the side rather than inadvertently walk over a snow bridge.

For those of us who feel confident of our skills dealing with snow travel in the summer a review of the later printing of the Last Season by Eric Blehm should make us a little more humble and hopefully a little more cautious.

I suspect that the two major trips I am planning for this summer will involve some over the snow travel and that will not deter me. You can bet that I won't relax and will travel with considerable caution and attention and will not relax until my feet are firmly planted on the ground!

Mike
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Re: Snow and Water levels 2011

Postby kpeter » Thu Mar 31, 2011 8:55 pm

Thanks Mike. Those are very useful hiking tips.

I can't find the 48" data. Here is where I have been going:

http://cdec.water.ca.gov/cgi-progs/quer ... SH&d=today

I don't mind walking across some snow but I do very much mind deep and swift river crossings. I have a near phobia about that after falling once and wiping out my camera but (very) luckily nothing more serious. I also don't like crossing passes with steep snow still in them, since I don't like carrying crampons and ice axe and am not in good practice with them. So I tend to be conservative in my old age on such matters! Hence my obsession about when things will melt out.
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Re: Snow and Water levels 2011

Postby oldranger » Fri Apr 01, 2011 8:39 am

Kpeter

It took a while to figure this out but go to CEDEC site. Look at left side and select station search. Enter BSH and search button. This brings up a table with the available data. At the bottom of the table are manual entry selections for depth and water content.

You can also do this for any monitoring site by going to the station locator selection on the CEDEC site. This allows you to bring up a map and you can select any site you are interested in. Some of the stations are no longer active but you can get access to historic data from them.

Hope this helps. It sure is fun to look at the various station. It boggles the mind to think about how much water is stored in the snow pack. By the way, the Oregon cascades have 125% normal snowpack which is a huge deviation from the norm for the Cascades which generally range between 90-110 and are not subject to the great variation that is typical in the Sierra.

Mike
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Re: Snow and Water levels 2011

Postby DoyleWDonehoo » Fri Apr 01, 2011 9:59 am

kpeter wrote:For example, last year in mid June the bridge at the outlet of Vernon Lake was surrounded by rapidly flowing water and a hiker was swept away just trying to reach that bridge.


I have crossed that outlet at about every season of the year, and you never know how bad it will be. Too often we had to wade. In the below picture, we waded from the large tree at the top middle of the picture to the shallows behind the little tree next to the bridge. This was early season with snow on the trail between Vernon and Tiltill Valley. :-k
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Vernon Lake Bridge
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Re: Snow and Water levels 2011

Postby kpeter » Fri Apr 01, 2011 1:01 pm

Thank you Mike, I was on the right page but had not noticed the manual data. That data is probably more accurate but is only once-month, sadly. Interesting parallels with 1998 indeed.

Thank you Doyle for those comments and that picture. By the time I was there in mid June of last year the water was down far enough that one could hop/jump/wade in one inch of water to get to the bridge. The ranger I talked to, however, said that the week before the water was moving rapidly around both ends of the bridge, so it must have been even higher than it was in your picture. I did not get details on what happened to the woman--where she lost her footing, how far she was carried, etc., except that she was medivacced out.

By the way, I camped around the lake on the North side and crossed that bridge on a stroll that evening. A cinnamon bear followed me over and decided to hang out near the end of that ramp to the bridge in your picture. I sat up on the trail watching him for half an hour wondering if he was going to guard the only way across the stream all night. Thankfully he didn't--he eventually moved along to sniff out a few other campsites and see if everyone had properly used their bearboxes. But for a while I was wondering what I would do to get back to camp if he decided to stay on sentry duty!
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Re: Snow and Water levels 2011

Postby oldranger » Fri Apr 01, 2011 5:38 pm

Kpeter

Re bear: Just walk down to a respectful distance and tell the bear you are going to cross and you can do it the easy way or the hard way his/her choice! If being polite doesn't work get a little aggressive but make sure he/she has a nice escape route rather than over you. If the bear was going to be aggressive toward you it had plenty of time.

Mike
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Re: Snow and Water levels 2011

Postby Herm » Fri Apr 01, 2011 11:29 pm

Wow, this is a great thread, with a wealth of good infromation provided. I was born and raised in Santa Ana and have lived in Orange County all of my life, and I remember (barely) the 1969 flood washing down the Santa Ana River and Santiago Creek (the confluence of which is still my parents' backyard). In 1998, Orange County, which averages around 13-14 inches of rain per year, received about 33+ inches of rain - interesting to see that in comparison to what accumulated in the Sierra that year. That was the year that I moved from the mesas of Yorba Linda to the hills of Anaheim, and saw probably most of that 33+ inches of rain that wet season.
That same year, in late July/early August, my wife and I hiked from Hwy 120 to May Lake, to Glen Aulin, to Tuolumne, encountering snow banks to 3-4 feet around May Lake (the High Sierra Camp was not even open, as we camped along the shore of the lake), temperatures were very warm, and some of the worst mosquitoes we have ever encountered. But still a great time!
Thanks for posting all this data.
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Re: Snow and Water levels 2011

Postby kpeter » Thu Apr 14, 2011 6:17 am

Here are the latest snow depths as of April 13

Format = Station; elevation; depth two weeks ago; depth on the 13th

Kibbie Ridge; 6700; 95.8; 61
Ostrander Lake; 8200; 156.1; 124
Slide Canyon; 9200; 147.6; 119
Charlotte Lake; 10400; 143; 112
Bishop Pass; 11200; 118.5; 96

As you can see, we had a warm first half of April and depths are already coming down. However, when I checked the water content the levels had not come down nearly as much as snow depth. It is getting warm enough to melt the top layers which drain into lower levels and refreeze, making our famous Sierra concrete. Still, this is the normal progression.

Looking at the progression at Bishop Pass I note that there are 40 inches of water content there as of April 13. On April 13, 1993, there were 40 inches of water content there. We seem to be exactly on the 1993 progression. In 1993 passes melted out before they did last year, even though 1993 (and 2011) had more snow than last year.

Conclusion so far: If April, May, and June all stay as warm as the first two weeks of April have been then this will not be a particularly late snow year for backpacking, despite the heavy snowpack. It all hinges on the next 8 weeks of air temperature.
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Re: Snow and Water levels 2011

Postby oldranger » Thu Apr 14, 2011 7:52 am

kpeter,

Key is water content which at this time of the year refers to ice. The more ice the longer it takes to melt. Some of the relatively lower elevation sites (+9,000 have over 50 inches of water. And you are absolutely correct. The temp and weather this spring will be critical factor. Last year my typical extrapolations didn't work quite right due to the cold and snowy spring. Right now I'm thinking that last weekend of june will be about the start of some fairly conservative backpacking opportunities and I'm scheduling my midsierra hiking beginning mid July and a high Sierra trip (up to 11,000) a couple of days later and about 10 days earlier than I would like but family obligations trump my backpacking schedule. I'm really looking forward to my September trip.

Mike
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