High Sierra Thunderstorm, Tuolumne Meadows

Alex Wierbinski's picture

By Alex Wierbinski - Posted on 11 July 2013

Video embed: 
See video

High Sierra Thunderstorms

A regular feature of High Sierra weather during Summertime are local thunderstorms.

These thunderstorms are the most powerful expression of the relationship between the Valley and the Sierra Nevada. During most of the year the weather in the Sierra is a product of a vast system of energy distribution operating on a planetary scale.

Typically, the storms that bring our Winter snows begin thousands of miles away in the Bearing Straight.

This is not the case for Summer thunderstorms in the Sierra.

These powerful storms are generated by local heat and evaporation generated in the San Joaquin Valley, pushed up the Western Flank of the Sierra on the wings of Pacific breezes, and cooled rapidly by the climb.
This violently transforms hot Valley air fat with moisture into cold air sweating moisture, and this transformation can be felt in Earth shaking thunder and seen as massive bolts of lightening highlighting torrential downpours, all topped off by great sunset shows as the storms tear themselves apart at twilight.

Delightful, but dangerous. Violent T-Storms are not always the outcome of Valley heat.

During Summertime heating trends in the Valley determine the daily progression of local weather in the Sierra. When temps are lower than 100 degrees in the Valley the evaporative clouds pushing up the Sierra are minimal, and the daily cycle of clouds and clearing will not threaten thunderstorms.

But when temps in the Valley hit 100 degrees the T storm mechanism can begin operating. If a heat wave breaks out in the Valley a multi-day "heat pump" can begin operating, with each day's rising temps pushing powerful storms like clockwork up the West flank and  Sierra Crest, to explode into violent thunderstorms and torrential downpours.  These daily storms die with each days sunset, when the energy source of this vast heat pump, the Sun, sets. 

It is each Sierra backpacker's obligation to observe the recent trends and changes in the daily weather pattern. If the pattern is forming daily thunderstorms (generally they form between 2 and 3 pm, but sometimes things get weird) it is your obligation to make sure any high crossings of open spaces do not coincide with nearby thunderstorm activity.

In this page's embedded video I had already arrived and set up camp at the backpacker's camp at Tuolumne Meadows before the thunderstorm broke out.

I was ready, as thunderstorms dotted the last couple of days of my trip across the North Yosemite Backcountry in late June and early July of 2013.

Listening to the rain tapping on my tent was delightful, while the thunder and lightening gave an edge of excitement to this otherwise tranquil scene.

Also See

Mountain Safety

High Sierra Weather Page

Tuolumne Meadows Backpacker's Map


More Lightening Information

Lightening Prediction Tools



Powered by Drupal, an open source content management system

Latest News: RSS FEED

Syndicate content

Support Tahoe to Whitney

The Tahoe to Whitney Trail Guide and Magazine are walked, written, funded, and supported by my efforts, with the help of kindred spirits and my sister.

We offer valuable Trail Guide, Skills, Weather, News and Analysis.

My goal is to get you out to see your natural and social potential. Help me keep this unique resource accessible and expanding towards its potential. We've a lot of miles to cover ahead...

If you feel these efforts are valuable, I'm cordially inviting you to support them, here:



I am currently working towards publishing the completed guide between Tahoe & Yosemite as an e-book, while converting this "blog" to a fine magazine format. You will like the results! Help Tahoe to Whitney reach its potential!


Why Support Tahoe to Whitney?
Mission Statement