Backpacking — Sierra Nevada Water — May 29, 2017

Sloshing ahead!

Data continues to point to snow in the Sierra Nevada high country late into the summer.  Here is the latest in the series of 2017 water supply reports for backpacking in the Sierra Nevada in California.

Where better to keep an eye on snow levels than at 11,000′ Mammoth Mountain?  Even though Mammoth has stopped updating its daily ski report on its website for the season, that is unless you ask them to put you on an email list, their cameras keep rolling.  Here is a shot from Mammoth’s McCoy Station this afternoon (May 29, 2017).


The visual data is impressive, but look at this list of snow survey stations provided by the Department of Water Resources.  Check out the % of April 1 mean snow water content recorded on May 26, 2017.  Keep in mind April 1 was almost two months ago; it is now almost summer time.  This is not the depth of snow on May 26; it is the depth of water the snow would leave behind if it were melted down and left in place.  This late in the season, the ration of snow to water is probably about 6:1 or more.  So, if there is 36″ of water content at a spot, the snow could still be about 18 feet deep at that location.  Bottom line — there is still a lot of snow up high.

With that said, snowmelt from the lower and middle elevations has made it to the lakes, streams, and rivers downhill.  The streamflows started to pick up dramatically in early May, but then a cold spell hit the Sierra and temporarily dropped the snowmelt and streamflows.  The flow rates now look to have jumped back up and peaked a few days ago.  With warm weather and rain in the forecast, flow rates may return and go even higher in the next few days as the last of the lower elevation snow disappears.

The streamflow graph (also referred to as a hydrograph) below shows the trend of flow in the West Walker River, which drains a large watershed on the east side of the Sierra Nevada, north of Mono Lake.  It is a good indicator of how the flows from snowmelt have increased over the last few weeks , because at this location the flow is largely natural and uncontrolled by manmade dams.  If there were dams above this location, the graph would look like more of a staircase, with steps appearing whenever the dam operator opened or closed the gates in the dam.  This  more natural graph increases a bit  each day as the sun shines, then recedes as temperatures drop overnight.  Again,  the cold weather in mid-May is evidenced by the significant dip in flow.


All this to say there should be plenty of water in the Sierra Nevada for 2017 backpackers.  In fact, it may be downright dangerous for some high country folks like our annual Pacific Crest Trail (PCT) thru hikers.    If you are planning to hike in the high country, you should be checking trip reports like High Sierra Topix.  A blogger on that string suggests you follow Instagram using #PCT2017 if you are hiking the PCT.

Keep on top of the data, and . . .

Happy (late) hiking!