where are those really good multiyear graphs on Snotel?

H

hayduke

New member
For the last few years it was easy to find graphs on Snotel (I am interested in the Snowbird station) where you could pick any combination of years back to 1990 and see the overlay graphs for snowfall , snowpack, water content etc. Does anyone know if these graphs are still there? I cant find those choices this year on the website.

Maybe it is a blessing, but all that I can find this year is 2008 (now) 2007 (last year) and average.
 
Please post the links in question. In the early 1990's I was referred to Snotel data, and I have usually found that it deals exclusively with water content and almost never with snowfall.

A Snotel station can be set up remotely to send daily info by radio. It weighs the snow on its platform and can thus determine water content and day-to-day change. Snowfall measurements require human daily monitoring.
 
Tony Crocker":1kg0k0ei said:
A Snotel station can be set up remotely to send daily info by radio. It weighs the snow on its platform and can thus determine water content and day-to-day change. Snowfall measurements require human daily monitoring.
Click to expand...

Standard snotels measure snow depth with a sonic sensor and do not need human input.

Heres a link where you can make graphs of precip, snow water content, and temps using archived snotel data. No snow depth option for the graphs on this particular site but I'm sure theres one out there somewhere.

Snotel Data
 
hayduke":263pkv3v said:
...it was easy to find graphs on Snotel (I am interested in the Snowbird station) where you could ... see the overlay graphs for snowfall , ... (etc.) ...
Click to expand...
The USDA Natural Resources Conservation Service (NRCS) is primarily interested in the amount of moisture in the snow pack. Previously it was necessary to measure the snow depth and weigh a column of snow to get the Snow Water Equivalent (SWE). Thus snow depths were often recorded for the old manual “Snow Courses”. For the most part, the old snow courses have been replaced by automated “Snotel” sites. These measure the weight of the snow pack on a “pressure pillow”, so that depth is not needed. However, a fair number of Snotel sites do have depth gauges. But, as Tony stated, historical snow depth data are very limited. Even though depth is measured at many of the sites, it’s often only available for the current water year. I think I’ll complain to the NRCS and ask them to make the historical depth data more available.

I’m quite sure that I’d previously found a set of NRCS or NOAA graphs that showed snow depth for the last several years. I can’t find them now. However, I did found a NOAA site that allows you to make a custom graph which includes snow depth back a few years. Go to:
http://www.nohrsc.nws.gov/interactive/h ... 0000000028

You’ll get a graph for the Snowbird Snotel for the winter of 2003/2004, which seems to be the first year with depth available. You can adjust the dates for other periods. The thick light blue line is the measured snow depth. The thin light blue line is the “modeled” depth. Also note an occasional anomaly where a very high unrealistic reading may be shown. The snowpack density is shown in purple. It’s the inches of water (SWE) divided by the snow depth in inches times 100. This is the density of the entire snowpack so the readings will be higher than the density of the top layer that we like to powder ski in.

If you just want to compare years and see what years had more or less snow than normal there are some graphs that measure the Snow Water Equivalent (SWE). In other words the inches of water in the snow pack. Here’s a link to a site that will allow you to taylor a graph for a given period of time. http://www.wrcc.dri.edu/cgi-bin/snoMAIN.pl?SBDU1 This link is for Snowbird. Click on the “Graph and Lister” link and change the YYYYMMDD dates to your desired range. The smooth blue line is the average SWE and the more jagged blue line is the actual SWE for the period selected. I found that the “extra large” graph size worked well on my monitor. Go to http://www.wrcc.dri.edu/snotel/ and find a “Drop-Down List” to fashion graphs for any Snotel Site, or select the UTAH link for a small scale map that shows site locations. Note that the “averages” are usually the 1971- 2000 values.

First of the month data (not a graph) for Jan – Jun (you select month and year back to 1997) are available at the following: http://www.wcc.nrcs.usda.gov/cgibin/sno ... state=utah Select the “LOST” report for the desired year. It appears that depth data were only saved since 2003 for Snowbird. (When and whether depth data are saved depends on the site).

Hourly snow depth data are available for a selected day (back to the fall of 2002) using the following link: http://www.met.utah.edu/cgi-bin/droman/ ... ?stn=SBDU1
This loads into an Excel spreadsheet which could be copied and accumulated into another spreadsheet which could easily have a graph produced. I think if you sign up, you can then get more than one day at a time.

Lastly, here’s a link that many folks aren’t aware of. It gives the current (midnight PST) SWE, the average SWE, departure from average, and the current snow depth and snowpack density: http://users.frii.com/global-cgi-bin/cg ... h&format=1
This takes a long time to load and sometimes isn’t available. Snowbird is found in the “PROVO R.-UTAH LAKE-JORDAN R.” basin.

Hopefully some of this will help you.
/s/ Cliff
 
Tony Crocker":seh7pdqp said:
Snow depth, yes. Snowfall, no.
Click to expand...
That's true. However, snowfall can be very ROUGHLY estimated by comparing the daily snow depth readings.

I've found that during cold periods with moderate snow fall the increase from one day to the next will be similar to the snowfall. Adding up the daily pluses will be similar to the period snowfall.

All bets are off duing warm periods. The snowpack will always settle and the difference from the previous day will be a negative, and yet there will actually have been some snowfall.

Some of our nearby snotel sites have readings every three hours and a few have hourly readings. I thought that might solve the above problem when snow pack is settling by adding up the pluses for the three-hour readings. However, I found that the depth gauges seem to "fluctuate" up and down slightly and by adding up the 3 hour readings pluses, I almost always got a value that was greater than the actural snowfall. Obviously using 1 hour readings would be even worse. I'm not sure what causes this fluctuation, but it's common to see a depth go from (for example) 10.1 to 10.0 to 10.1 etc, several times.

I still like to use a spreadsheet and pivot table to add up the daily pluses and compare it with known snowfall.

Maybe someone could develop a regression equation for this.
/s/ Cliff
 
I spend way too much time at this as it is. Having to commit to daily tracking for even a handful of areas, I'm not willing to do. After all, I like to spend some of my time in the winter actually skiing :wink: .

From a scientific standpoint snowfall is an imprecise measure. Only skiers and avalanche researchers care about it. When the Mt. Baker record in 1998-99 was being certified, I think the standard that NOAA wanted was: Manual measurement at least once but no more than twice per day.
 
hayduke":14aklomj said:
I found the link:<http://www.cbrfc.noaa.gov/snow/station/sweplot/sweplot.cgi?SBDU1
Click to expand...
Hayduke,
It's a neat graph, but I think if you check it out, the values shown are NOT snow depth. They are the Snow Water Equivalent (SWE). That's what's shown on the left Y axis of the graph and the values seem to be correct for SWE and not depth. Note that the average max was about 42" and the 2007 value was about 30". That seems about right for the Snow Water, but I'm sure the max depth was quite a bit more.

Check out the standard NRCS graphs at: http://www.wcc.nrcs.usda.gov/snotel/sno ... 6&state=ut
Look down to the Snow Water Equivalent line in the Current Water Year Column and click on the Daily Graph link. You'll get a current year and an average graph that looks exactly like yours. You can select previous years too and the 2007 line for SWE looks exactly like yours.

I'd expect that the actual depths would be about 5 times (or more in the early winter) the SWE values.

However, if you DO find a way to get snow depth graphs, be sure and post it.

The above link gives links to numerous Snowbird tables and there are several TABLES that do give the CURRENT YEAR depths and they aren't that hard to get into an Excel spreadsheet and graph. I have have a spreadsheet set up so all I have to do is right click and select "Refresh" and the current year data will be updated.

I sure wish we had your snow depths. Where I cross country ski, the average maximum depth is only about 40". Although our downhill ski area probably averages 80-100" for it's max.

Good skiing,
/s/ Cliff
 
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