4. What to Expect
This Chapter is intended to give you an impression of the conditions on the JMT. This can serve as a guide to choosing your gear and making your preparations. Later, you can compare your thoughts with a gear overview in Chapter 6 Gear and my personal experiences in Chapter 7 Plan and Go.
a. Weather & Conditions
Temperature
The most important measure in deciding what kind of clothing to bring is the expected temperature. In order to estimate temperatures along the trail, it is useful to use a lapse rate. As a rule of thumb, deduct… To read more, click here
Remember that you will be at altitudes well above 9,000ft for a great portion of the trail. This means that while temperatures may be fairly low during the day, due to low humidity and aerosols, the sun will be merciless. At the same time, this source of warmth will set early behind other peaks and temperatures will drop quickly. Additionally, any water you find for washing clothes and yourself will likely be around 40-60°F / 4-15°C. Keep this in mind when planning your arrivals to camp. At the end of a long day, your energy and body heat fade. And while you will want to wash off dust and sweat, regaining a comfortable temperature becomes a challenge after sunset. This means, the earlier you can set out in the morning, the more distance you can cover before the sun is too hot, but also arrive at camp and get washed up while the sun is still out and strong enough to dry/warm you.
Precipitation
From June to September, when most hikers hit the trail, it will only rain occasionally – if at all. However, there is a fair chance that it will rain at least once while you are hiking, especially in June (see Table 1).
Table 2 reads as follows: Taking the row of July: July has an average precipitation of 0.3in./1cm, historically wet Julys reached up to 4.2in./11cm; there is usually one day of rainfall of greater than 0.01in./0.3cm and one with more than 0.1in./3mm; there are zero days with any stronger precipitation let alone snowfall. So in a nutshell… To read more, click here
Other Conditions
Wild fires are unpredictable but common occurrences in California. Most recently in 2013, forest fires devastated large areas in the Yosemite Wilderness as well as around Mammoth. The fires never got close enough to the JMT to pose an immediate threat to hikers, but the partially thick smoke put stress on breathing and reduced visibility.
While you cannot prepare in advance for a wild fire, you can take the right precautions if you are aware of wild fires in the area… To read more, click here
b. Trails
The JMT is wonderful. It is mostly a somewhat narrow, single lane trail that feels like a minimal disruption to the surrounding wilderness. As the trail is frequented (scarcely) by horses and mules, there is never a need for climbing (involving your hands). However, there are very steep, winding passages with sudden drop-offs to the sides, where you wonder how these large animals do it. The drop-offs and ledges also call for you to be fairly resistant to heights.
The predominant surfaces you walk on are… To read more, click here
c. Campsites
Regulations
Park services and common sense command you to use established campsites. These campsites are neither marked nor equipped with a picnic bench. They are simply flattened patches that should be in accordance with the selection guidelines (i.e. not on vegetation and at least 100ft away from water and trails). However, if you find an established campsite that does not meet the required distances, it may still be reasonable to use it instead of flattening other vegetation. Established campsites are plentiful along the JMT, giving you a wide variety of spots to choose from.
Wood campfires are only allowed in pre-existing fire rings. Generally, campfires are prohibited above 9,600ft in Yosemite, above 10,000ft in John Muir and Ansel Adams Wilderness as well as in San Joaquim and Kings Canyon National Park, and above 11,200ft in Sequoia National Park. There are some additional local restrictions and there may be strict “no fire” rules for all altitudes in times of drought. That said, refraining from campfires altogether – decreasing the risk of wild fires and conserving the limited timber – has a strong advocacy.
Choosing a Campsite
When choosing a campsite, consider two factors: climate and strategy.
Climate will be the more important factor. Remember to avoid… To read more, click here
Strategy plays a role in choosing your campsite along the way with regard to daily distances and strenuous segments. You will find that certain areas at the foot of a steep incline will have… To read more, click here
For considerations regarding daily distances, see the next Chapter 5a Your Itinerary.
d. Water
There is plenty. Even in late August, after three months of hardly any rain, the abundant snowfalls of winter and spring still feed the countless rivers and lakes. Large parts of the JMT lead you right along beautiful bodies of water – babbling in brooks or lying peaceful, mirroring the peaks. You rarely walk for more than one hour before a stream crosses your path. So water availability is not an issue.
While the waters look clear, they may be contaminated. The global prevalence of the protozoan Giardia lamblia and the E.coli bacteria does not stop in the Sierra Nevada. Both lead to diarrhea and abdominal cramps, sometimes with a delay of 5-15 days post exposure. Fortunately, both can be filtered and/or killed with common treatment methods (see Chapter 6d Food & Drinks). Equally important, however, is a good camp hygiene to limit the spread of microbe-borne illness – especially after a squat with a view.
In order to not to add to the problem, make sure to always… To read more, click here