COLORADO SPRINGS, Colo. — Colorado’s population continues to boom, meaning a lot of beginners will be trying Colorado activities for the first time with each new season. One of the most alluring is summiting one of the state’s iconic fourteeners. If this is on your summer bucket list, here are a few things you should know before you hit the trailhead.

1. Altitude sickness is a very real thing.

The higher above sea-level one gets, the less oxygen there is in the air. This can lead to a serious condition called “altitude sickness.” In its mildest form, altitude sickness tends to feel like a bad hangover. It will make you dizzy, lightheaded, and achy. In its most serious form, altitude sickness can lead to passing out and even death. This condition can affect anyone, regardless of physical fitness, and it tends to be more prevalent when someone is physically active at a high altitude. Most sources pinpoint 8,000 feet as the elevation where symptoms start to show, but this can vary from person to person. A few tactics to help prevent altitude sickness include acclimation (letting your body get used to the higher altitude), drinking plenty of water and consuming mostly carbs, as well as breathing deeper, thus giving your body more oxygen (some even suggested a portable oxygen tank). Most importantly, know the initial signs of altitude sickness and move to a lower elevation immediately when they start to develop.

2. All mountains aren’t created equally.

Some mountains are much harder to climb than others. When you’re trying to summit a peak, be aware of the route you’ll be taking, planning ahead to know what it will require. Never underestimate a climb, even if you’ve heard something along the lines of “it’s not that bad.” One website that can be helpful with Colorado fourteeners is 14ers.com, which even has a list ranking the difficulty of all fourteener summits in the state. Some mountains require years of training to tackle and many require technical climbing where a single mistake can mean death. Study the mountain you want to climb. Be aware of its features and be aware of whether or not climbing it is within your skill level. A few Colorado fourteeners that can be good for beginners include Grays Peak, Torreys Peak, Mount Sherman, and Quandary Peak, but even these “easier” mountains can be deadly.

3. Bad weather can kill you.

One of the biggest mistakes that beginners tend to make is not understanding how high-altitude weather works. The general rule of thumb tends to be “be back below treeline before noon,” with the reason being that intense mountain storms tend to roll in like clockwork after that. At first sign of bad weather, the smartest decision is often to turn back, even when that means you might not bag a summit. Lightning, wind, and freezing rain can kill you and many times these storms can appear with little notice. Take this point especially seriously. Mountain weather is not something to mess around with, regardless of your skill level.

4. Don’t overestimate your abilities.

Yes, you’ve hiked a trail that’s 10 miles long … but that wasn’t a rugged trek above treeline. Yes, you can run a half-marathon with ease … but that half marathon doesn’t require slow scrambling over loose rocks where speed simply isn’t an option. When you’re climbing a Colorado mountain, expect some of the hardest terrain you’ll ever encounter. There might be snow, ice, and loose rock that make moving even just a mile per hour seem fast. The only way to know how you’ll do climbing in these conditions is to try it on the easiest possible scale and then go from there. Getting in over your head on a mountain climb can result in serious injury, necessity of an expensive rescue, or even death. Be aware of your own abilities and don’t overestimate what you’re capable of doing.

5. Always leave no trace.

Mountain trails are often very remote and difficult to clean. Never leave anything behind, whether it’s a banana peel, leftover food, trash, or feces. Because these ecosystems are relatively untouched, any abnormality can have an impact. Follow the Leave No Trace principles religiously and consider bringing along a trash bag to clean up after those that don’t.

6. Plan for the worst.

When you’re climbing a mountain, preparation is key. When things go wrong, preparation can save your life. Bring food, water, and survival tools with you. Tell people where you’re going and when you’ll be back before you leave. Familiarize yourself with features of the landscape so that you might still be able to determine direction when all else fails. The mountains aren’t the place to take caution lightly. If you’re careless, you might not get a second chance.