Safety Tips in Yosemite National Park

The Merced River is the main river running through Yosemite Valley, but there are many trails that will take you along the edge of a river. Particularly in the spring and early summer months (April through June), the water level is high and the current is strong, so don't be a dummy and try to go swimming. There are signs along the trails that warn of this and at the top of some of the waterfalls the signs will say something like "Danger. Do not swim here." Duh!!!

There are some more peaceful spots in the park where you can swim, many of which are clothing optional.

Yosemite is one of the most loved parks in the United States. It is fairly close to the vast population centers of LA and San Francisco. In short, there will be people at the most popular vantage points no matter the time of year and no matter the time of day. And people being people, they will be certain to do things that will annoy you. Grin and bear it. Don't let the people destroy your enjoyment of the awesome beauty that is on display. Yosemite is mightier than the masses and will be here long after we have passed this way.

Although Yosemite attracts large crowds of people during the summer, there is no cell phone service within the park. If you want to be reachable by phone while hiking/driving around the park, you will need to rent a satellite phone.

Yosemite National has easy access to very high country on Tioga Rd, so your chance of receiving some form of altitude sickness is possible. Altitude sickness, or acute mountain sickness (AMS) is a disorder that generally occurs when you reach an altitude where your body is no longer able to receive enough oxygen from the thinner air. AMS usually starts occuring around 8,000 feet, though for some people it may occur at lower or higher elevations. It's not suggested to drive from the Bay area to Tuolumne Meadows and hike up Mt. Dana in the same day. People who have spent a few days in Yosemite Valley (4,000 feet) should be able to get to Tuolumne Meadows without major AMS problems. AMS symptoms are usually just headaches, but fatigue and insomnia are also possible. Generally, AMS is not too serious, and anyone suffering from it will improve after they descend to a lower elevation. However, it's always a good idea to acclimatise before heading to a relatively high elevation area. Roads in Yosemite reach 9,945 feet and mountains reach over 13,100 feet, meaning that there is also possibilities of HAPE and HACE, more dangerous forms of the altitude sickness. If you are over 10,000 feet (3000 meters) and feel severe discomfort, it's a good idea to descend to a lower elevation.

Although the creeks and lakes in Yosemite look clean and fresh, and you know there's no upstream pollution sources, it's recommended that you don't drink it. This applies to not just Yosemite but also throughout the Sierras. The natural water here is often contaminated with giardia lamblia which can be carried by human and wildlife. If you have to be in the wilderness for days and cannot carry sufficient water, try boil and filter it before you drink.

Emerald Pool is located just above Vernal Fall along the Mist Trail. As seen in photo, the Pool has several natural water slides, some longer than the ones you have in your home swimming pool. Be warned, these natural slides are made of granite much rougher than sandpaper. They can easily wear through your pants and burn your behind. No wonder I saw a few youngsters walking down the Mist Trail funny...

Don't do this in Emerald Pool. Only do it at home !