Jimmy--wear jeans all you want, but once you try hiking in something that weighs less, dries quicker, and can be converted to shorts in about ten seconds, you will change your mind.

BTW, here the page on dangers on the trail from our website:

Dangers on the Trail
The irony about the Sierra Nevada is that the things that most people worry about really aren’t much of a problem. And the things that really can create life-threatening situations are pretty much off the radar for most hikers. Weird, huh?



In all of our years in the Sierra, we’ve never seen anyone get bitten by a snake or attacked by a bear. But we have seen people in varying stages of hypothermia and dehydration. And we’ve seen other people who were well on their way to problems in that regard. So what is the single biggest danger in the Sierra Nevada for hikers? We think it is hypothermia, followed by dehydration and getting lost.



Hypothermia



Simply put, hypothermia is when your body can no longer maintain that perfect 98.6 degree temperature, and starts to cool down. That is a bad thing—because when your body starts to feel as if it can’t keep you warm, it tends to focus on keeping your vital organs warm: your torso. And that means less blood to your arms, legs, and head. Your head is where your brain is…and less blood there tends to make to you tired, sleepy, and a little stupid. When that happens, the most logical solutions to the problem may not appear so logical to you---and you start making mistakes that only make things worse.



The obvious solution is to get warm. The even more obvious solution is to not get cold at all. That means paying attention to the weather reports, understanding how hypothermia can happen, and bringing along enough clothes to make sure that you are prepared for any situation. Getting wet makes hypothermia much more likely, because the moisture saps your body of heat really fast.



How likely is that? We have seen rain during every month of the year in the Sierra, and above 10,000 feet, that rain can become snow without a second thought. So yes, be prepared for rain and snow, even if the weather looks perfect. Even on a day hike. Waterproof outer layers should be in your pack. Fleece inner layers should be on your body, or available. And if you are staying overnight, shelter should be an option wherever you are.



When the weather turns cold and wet (and this can happen in fifteen minutes in the mountains) don’t plod on until you really start to feel cold, or until you are ready to make camp. That’s a sure way to get stupid, and then the rest of your decisions will be questionable. Immediately put on your rain gear, and look for places to set up your shelter. Don’t get cold and then try to get warm---stay warm and make smart choices. Warm and sheltered, your mind and body can survive for many days. Cold and stupid, your chances go way down quickly.



Our rule? If you start to think about hypothermia, that’s the time to do something about it. Don’t wait until you are sure, because you won’t be able to trust your mind to make a good decision by then.



Dehydration



In the High Sierra, the air is so dry and thin that you really don’t notice how much sweat is evaporating off your skin. It is gone before you notice it. (If you are wearing a pack, the back of your shirt may well be soaked—but the rest of your body will be dry. Pay attention to your shirt, not the rest of your body!) Because keeping your body hydrated is really important.



On the one hand, your body can survive for two to three weeks without food, but it can only survive a few days without water. But there is an even worse danger with dehydration: it can also create a real imbalance in your electrolytes, and that makes your brain do all sorts of unexpected things, from headaches and hallucinations to just plain stupid.



There’s that stupid problem again.



We have a simple rule about dehydration, too. If you don’t have to pee every couple of hours, you are probably getting dehydrated. Stop, drink all the water you have, and then make a plan for how you are going to proceed. You never get any prizes for arriving at a water source or a campsite with lots of water in your bottles. You often get punished for making dumb mistakes because you are dehydrated.



If you have done much hiking, you have seen dehydrated hikers. They are plodding along, mouth open, gasping. They may even tell you that they are not dehydrated, because they are not even sweating. If you are not sweating during a hike, it’s because you are so dehydrated that your body can no longer produce perspiration. And it’s a function of that dehydration that your brain thinks that this is a good thing. Stupid.



People who are dehydrated make dumb mistakes, like passing up a water source to make better time to the next one, or missing a trail junction because they aren’t paying attention. And then they get more dehydrated. And they make more stupid decisions.



Again, the solution is preparation. Take plenty of water. Plan your trip so that you are sure where you can get water, and fill up. Drink until you have to pee, all during the day. And if you think you are getting dehydrated, drink and rest until you know you are not. If you think you are not dehydrated, that isn’t good enough!



Getting lost



It is actually pretty hard to get lost in most of the entry level hiking areas of the Sierra Nevada. The trails are well marked, and there are enough people on them to ask a question or two if you are feeling a little confused. When you add those facts to the great USGS website that allows you to get free topographical maps every hike, and there is really very little excuse for getting lost in the Sierra.



Except that people do it all the time.



We’ve met people in the Sierra who were literally FIFTEEN TRAIL MILES from where they thought they were, and it had only, in the previous ten minutes, occurred to them that something might be wrong. It was after 3 p.m., and they had one bottle of water between the two of them, no warm clothes, and about 9 miles to hike before nightfall.



As with the previous two dangers, the first solution is to be prepared, and not get lost at all. You should always have a compass and map, and know how to use them. GPS units are great, but they can sometimes lead you to within 500 yards of your rescue: the problem being that those 500 yards are straight up or down a cliff. And when you are dehydrated or hypothermic, you think maybe that it wouldn’t be too hard to climb down that cliff. After all, it’s only 500 yards! Ahem.



Don’t get lost. Use a map, and track your progress on the map. Look for landmarks as you go along. If you don’t find them, little alarm bells should start ringing in your head. When you do find them, confirm them on the map, so you know where you are. It often helps to do these calculations with everyone in your group—just to make sure that your navigator isn’t a little confused.



If you do get lost, don’t panic. The best thing you can do when you are lost is to sit down, have a nice snack, drink a lot of water, make sure you are warm, and think. Go back to that map and find where you were the last time you were sure you were on the trail. And then look for solutions. If you are on a trail, DO NOT LEAVE THAT TRAIL! Sometimes it’s just a question of you getting tired, and you having slowed down. Another ½ mile and your destination will appear. Sometimes you have taken a wrong turn. Sometimes the trail is poorly marked, and you’ve lost it. Sit down and think. It is ALWAYS better to wait for someone to come along than it is to start running.



Whatever you do, don’t start running up and down the mountains in a panic. If you do that, you will not drink enough water. You may get hypothermic. And you will almost certainly make some really bad decisions. With luck, you will get found before you do something stupid. But every year someone gets lost in the Sierra, and doesn’t get found until they have died. Don’t get lost.



Altitude and Acclimatization

No, this doesn't mean that you should try to air condition your tent. But at 10,000 feet, your body is getting a lot less oxygen than it does at sea level, and that has some real repercussions. While altitude sickness won't generally kill you at the kinds of elevations we see in the Sierra, (the Himalayas are another question!) it can make you really unhappy. And that's no fun for you or your companions.

What are the symptoms? Similar to de-hydration, you can first notice a headache, and general weakness. You often lose your appetite, and this can lead to full-blown nausea and vomiting. And a worse headache.

What fun!

The solution is to acclimatize slowly. M swears that she always does better when she spends a night at 3000-5000 feet before we head up into the high country. And she does much worse if we just drive up and start hiking. The worst case we ever had was a day when we drove up from sea level, set up camp, and then climbed Mt Hoffman, which is over 10,000 feet. M felt awful, and continued to feel awful even after going to bed early. She woke up in the middle of the night and vomited numerous times, entertaining the neighbors in the campground.

The next morning she felt pretty good, and for the next four days we hiked at altitude without any real problems.

So take it easy. If you feel bad, stop, rest, and even head back downhill.

And lay off the alcohol--a really bad idea at high elevations! It both dehydrates you and makes you stupid!

Wild Animals!


Ah! This is the stuff that everybody wants to talk about. Wild bears who attack campers in the middle of dinner. Ferocious pumas who lie in wait behind every tree. Snakes that crawl into your sleeping bag at night!



Sorry. Doesn’t happen. Since 1980 there have been a total of twelve reported attacks by black bears in California. That’s an average of less than one attack every two years. Most occurred in developed campgrounds or rural urban interfaces, not in the wilderness. None were fatal. In that same time period, there have been exactly the same number of reported puma attacks—most near the rural urban interface, and none in wilderness areas. Almost all involved children or small adults. Roughly 800 people this year will be bitten by rattlesnakes, and one or two of those bites will result in death.



So you are not going to get killed or eaten by wild animals. In contrast, some 370,000 Americans are bitten by dogs badly enough to need treatment at the emergency room, and nearly 4,000 people will die in traffic accidents in California this year. If you want to be safe, get out backpacking in the high Sierra and STOP DRIVING YOUR CAR!



Actually, the only death attributed to a wild animal in the history of Yosemite National Park was a young boy who was killed by a deer. The boy was attempting to hug the deer to pose for a photo, and the deer kicked him, slicing open an artery.



Again, we have a few solutions. When you are in the wilderness, understand that you are in wild country. Pay attention. Bears are attracted by odors of food, so limit the amount of food smells you create. Store your food in bearproof containers to keep them from getting used to the idea that hikers mean food. Most developed campgrounds in our parks these days provide steel bear boxes for your food, and since those have been installed, bear damage to vehicles and camping equipment has drastically declined.



Pumas generally attack small people who are alone. They attack from behind. If you see a puma, stand up tall and face it. Fight back. Scream for help from nearby hikers. Write about it later, and make lots of money from the TV movie.



Rattlesnakes generally try to avoid people, and often will start to take defensive action when they feel your footsteps approach. Leave them alone. Don’t put your hand where you can’t see, and don’t climb cliffs blindly.

Want some really interesting statistics? 130 Americans are killed by deer every year. 65 are struck by lightning. 100 are killed by bees. 20 are killed by cows. Makes you wonder, huh?


Most importantly, drive very carefully to the trailhead. Your chances of dying are 4,000 times higher on the highway than they are on the trail.