Jan 1, 2016 Backpacker Alert: Tracking Opening of 2016 Backpacking

Alex Wierbinski's picture

By Alex Wierbinski - Posted on 01 January 2016

Hey Hikers,

Happy New Year.

With the advent of the new year many of our thoughts are turning towards planning Summertime backpacking trips.

Just when Summertime conditions emerge along the Sierra Crest is of great importance to large numbers of John Muir Trail and Pacific Crest Trail hikers.

The past eight years have offered the earliest string of openings in history. These have been far earlier than historic averages for clear trails along the Sierra Crest.

My Review: 
2009-10        had a weak-normal Winter.
2010-2011   had a huge Winter and Spring.
2011-2012   had a very weak Winter.
2012-2013   had almost no Winter.
2013-2014   had no Winter.
2014-2015   had no Winter.
2015-2016   having Weird El Nino Winter.

This year we are seeing a "reversion to the mean," though this is being delivered through a set of uniquely unbalanced Forces of Nature.

We are kicking off this year's tracking of the evolution of conditions from Winter to Summer with an email from a member. He's planning an early-Spring JMT hike that requires careful monitoring of conditions to ascertain the viability of his start date.

I figure a lot of us are in Caleb's situation, planning trips and monitoring conditions. Here's Caleb's inquiry, and my current analysis of the weather situation.

From this point out our weather observations will be tuned to understanding the evolution of conditions to predict clear trails along the Sierra Crest.


Hey Al, 
I have my permit for the JMT all squared away. Looks like May 17 is the start date out of Yosemite Valley depending on the snow fall.

It'll make or break the trip since I have to hike out of season. Which leads me to the question of what tools/website is best for tracking the overall snowpack depth along the JMT?

I probably won't have to pull the trigger on the decision to go or not until mid April but I'd like to see where things are trending.

Thanks for your help and happy holidays!

Happy trails,

 Caleb .

Hey Caleb,

Good news, bad news.

Good News First.

I track the annual evolution of Winter to Spring to Summer carefully:

High Sierra Weather

The tools linked to above are the best I can find tracking the growth, status, and evolution of the snowpack during its annual evolution through Winter to Spring to Summer conditions, and back again.
The rest of the page around these snow reports give us a wide scope of observations monitoring the forces controlling and timing the evolution of the seasons in the High Sierra.

Oh, and here's the MesoWest High Sierra ground reporting stations. I find these really helpful for tracking snow conditions at different elevations and aspects:

MesoWest Ground Stations

Scroll up from MesoWest for the other available ground reporting networks in the High Sierra.

Bad News:

I put the likelihood of a May start at ZERO.

I base this on the "best" case scenario for May start-dates within the current meteorological framework. ZERO.

This zero is based on the current snowpack and the El Nino.

I don't care how powerful the blocking ridge is, nor how weak and weird the Arctic is. Enough of that El Nino moisture is going to hit the Sierra to produce an average to above-average snowpack.
An average or above average snowpack will not clear from the crest until late June. Maybe mid-June, depending on the temp profile. It has been very warm, and the El Nino may even kick Spring temps up another notch!

If the El Nino DOES line up with the Sierra, rather than being mostly deflected around it, as my prognostication above assumes, the Sierra will not open at all. The Sierra will be pounded by record snowfalls. In that scenario the Sierra will open in August. Late August! I put this outcome at somewhere South of 30%.

To understand what you are watching in the sky I have written a "Backpacker Alert" describing the mechanisms controlling the distribution of El Nino energy/heat/moisture here:

September Backpacker Alert

I wrote this describing the evolution of Fall to Winter in terms of the interaction between the forces directing El Nino moisture. The status of these forces was then and is now controlling the distribution of El Nino moisture and heat.

The mechanisms controlling El Nino distribution scenarios are described in the middle of that Alert.

Trends began establishing themselves by December:

December 11 Backpacker Alert

Updating the evolution of El Nino Winter conditions since those Alerts we now note that the Pacific High has fully and powerfully established itself, the Arctic is as weak and warm as has ever seen in human history, and this record El Nino is humming along pumping out titanic amounts of energy, which also happens to be crushing global weather patterns.

 If you read my December "Alert" text you will understand that this means much of the El Nino moisture will continue to be deflected around the Sierra if the current configuration of these global-scale forces persists. I rate this scenario as the most likely outcome. I currently put this outcome at around a 60% probability.

Yet I anticipate the blocking action of the Pacific High will break down at least a few times, and the Sierra will get "hosed" during those breakdowns, which is the basis of my average, above-average 2015-16 snowpack prediction above.

May is buried during an average year.

If the Pacific High breaks down completely El Nino will leave the Sierra with at least 20 feet of snow in May. Maybe much more.

Because of these conditions I put the chances of an overwhelming snowpack followed by a catastrophic Spring Thaw due to a freak heat wave at 10%.

That means I am currently rating the chances of a once in 75 year catastrophic thaw event higher than the chances of clear trails over the Crest in May.

I can foresee weather scenarios that would work with your May plans, but at this point in time I rate them at ZERO chances of happening. But Nature is most flexible, even surprising.
These current outlooks will change with alterations in global and regional weather conditions as the seasons progress and change.

Monitoring those conditions and their changes is the job of the rest of the Weather Page. We have tools tracking the El Nino and Pacific Weather Maps to observe how the Pacific High affects the distribution of its energies approaching the West Coast of North America.

You can follow each of these tools to their technical and theoretical basis to find the analysis of NWS forecasters. I am better than them at certain things, worse at others, but my analysis stands on their shoulders...

My advantage is direct contact with the weather, rather than just relying on theory. I believe real engagement works to expand my perspective in certain areas of observation.

I have closely noted the actual weather changes in the field for decades, not just the changes as reported through networks of sensors...

I see Nature expressing changing characters.

Nonetheless, all our monitoring tools and observations will have to show significant changes in meteorological conditions in the Central Pacific for your plans to work.

Sorry to be the bearer of bad news, but that's the way things look right now. Clarity first, analysis second, decisions third, feelings last.

There are other Spring hikes if the weather and snow in the High Sierra are deep.
I would continue with all hiking plans up to the last minute. Deflect to a ten day hike up and down the Lost Coast, then head North to circumnavigate Mount Olympus (Olympic Penn) after, if the Sierra will not open.

The Sierra will likely be clear of snow when you are done along the Coast.

 There are amazing trips into every character of every season. The trick is figuring out where they are for you during each year.

Happy Trails




Feb 1 Backpacker Alert


2017: Example of Huge Snowpack Year


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