but be warned: you run the risk of having storms build and having no real way of seeing them coming until that first flash and boom.
If you can feel or see electricity in your hair, the storm is forming right above you. This is an especially dangerous situation—if you’re this close to the storm, it’s advisable to drop metal items—such as hiking poles, snowshoes, ice axes, and so on—and recover them later.
Local forecasts are good general indicators, but they do not apply to the variable conditions at elevation. The following sections discuss such conditions in greater detail.
Be prepared for bad weather. I bring a sturdy Gore-Tex shell and light rain pants on every hike, even when the weather looks clear.
Reading the Clouds
Many of Colorado’s days start off sunny and clear, often with a small smattering of clouds harmlessly hanging in the sky. As the sun begins to heat up the atmosphere, radiation and wind cause moisture to evaporate and rise. Air becomes less dense as it warms, creating lower air pressure—the perfect canvas for storms. Moisture that rises with the warm air eventually cools and forms clouds.
Be very wary of cumulus clouds if they begin to have dark, flattened bottoms and start to grow into towering pillars that reach high into the sky. A wise safety rule: When puffy white clouds begin to turn an angry shade of gray, it’s a good time to assess your position on the mountain.
The clouds that form over the course of a typical Colorado day can cue you into developing weather. Cumulus clouds look like puffy, cottony towers that initially form as individual mounds. Their presence indicates that the cycle of weather has been set in motion, with moisture cooling on high. As long as they remain spaced out and their bottoms remain fluffy and white, you are in no immediate danger. When cumulus clouds begin to build and fuse together, the sky will become dense, with individual clouds being less distinct.
Be very wary of cumulus clouds if they begin to have dark, flattened bottoms and start to grow into towering pillars that reach high into the sky. When this happens, cumulus clouds transform into cumulonimbus clouds, which most people recognize as thunderheads. These powerful clouds are the bringers of lightning, rain, snow, thunder, and hail—it is very important to pay attention to cumulonimbus clouds, especially if it is after noon. A wise safety rule: When puffy white clouds begin to turn an angry shade of gray, it’s a good time to assess your position on the mountain—cumulus clouds can build very quickly, forming storms from clear skies in less than an hour.
Other clouds you may see in Colorado include:
Stratocumulus clouds resemble darkened cumulus clouds lumped together. Unlike the epic, storm-nurturing cumulonimbus, stratocumulus clouds indicate a cold front and precipitation, often free of lightning and thunder (but not always). These clouds are common in winter and during colder days.
Lenticular clouds are the sleek, smooth clouds that arc like the bubbles in a lava lamp. These high-altitude clouds are indicators of strong winds and changing fronts; they often precede bad weather, which will generally arrive within 48 hours.
Nimbostratus clouds form a uniform, gray cloud cover below 8,000 feet that creates fog and rain. It is often possible to climb above these moisture-laden systems to clear weather above.
Cirrocumulus clouds are wispy, white, distant clouds that often form in flat sheets (such as the mackerel sky). These high-altitude dwellers form above 20,000 feet and are stabilizing clouds, meaning they carry no precipitation.
Similar in form to cirrocumulus clouds are altocumulus clouds, which form from 8,000 to 20,000 feet. Altocumulus clouds have the same globular, wavy appearance as cirrocumulus clouds, but the white is interwoven with darker gray patches, indicating an oncoming cold front and potential storms later in the day.
Barometers Many people who venture into the outdoors have barometers built into their watches, GPS units, or other electronics. Barometers measure atmospheric pressure; as a general rule, lower atmospheric pressure indicates bad weather, while higher pressure is a sign of clearing weather. Keep in mind that atmospheric pressure drops as you ascend, even on the clearest of days. I’ve learned to pay close attention to the fluctuations in my barometer when sketchy weather begins to blow in—a fast drop in pressure nearly always means storms are coming. Barometers aren’t perfect in predicting storms, but they do give you one more clue in predicting mountain weather.
Lightning Pressing your tongue against the terminals of a standard nine-volt battery creates a mildly uncomfortable shock that indicates how much charge is left in the battery. Multiply that voltage roughly 5,555 times and you have the power behind a normal lightning bolt! Anyone who has ever been caught in one of Colorado’s brief but violent storms knows the fearful helplessness one feels when at the mercy of such a powerful and unpredictable adversary.
Lightning travels far too fast for a person to outrun and may strike several miles away from the visible center of a storm, even under clear blue skies. Many people only think about the most obvious danger from lightning: getting hit by a thunderbolt. While a direct strike is the worst thing that can happen, it’s not the only threat. Splash strikes occur when lightning jumps from the initial strike target to surrounding areas. Ground strikes (or step voltage) hit the hiker from below as lightning dissipates into the surrounding ground. Contact strikes occur when a person is holding something that absorbs a direct strike, such as an ice ax or tent pole. Finally, shock wave strikes happen when a nearby bolt is powerful enough to generate a shock wave that can easily knock a large man off his feet.
Safety in Lightning Storms
Obviously, avoiding storms is the best practice in the mountains. Weather forecasts should always be referenced before heading out. However, even the most prepared and knowledgeable hiker can be caught in fast-building storms. I’ve seen storms metastasize from clear blue skies directly overhead in less than 15 minutes (and at all times of the day).
If you are caught in a storm, stay calm. You must assess the danger quickly and act accordingly. Storms don’t give you time to factor in all the variables: if you need to seek shelter, it must be done without hesitation. Following are a few rules for finding relatively safe places in lightning storms:
Stay away from water, including the faux safety in gullies and streambeds.
Always try to get as low as safely possible, hopefully back into tree line or the lowest areas in open meadows. Never stand under trees in open areas—keep moving to safer areas.
Immediately get off summits and ridges, even if it means diverting to an off-trail pocket of safety.
If you smell, hear, or feel electricity in the air (examples: your hair stands up or your snowshoes start to hum), move down quickly! Even if your lungs are burning, move as fast as you can to safer places. Sometimes you have to suck up the pain and just keep moving.
Space out a minimum of 60 feet from your companions (think of this as the distance between a pitcher and catcher on a baseball field). If one member should get injured by lightning, maintaining this distance will keep other party members from being hurt.
Stay away from metal objects such as hiking poles, ice axes, and climbing gear. Tent poles are especially dangerous—if you are stuck in your tent, make sure that you are not in contact with the poles and you are insulated from the ground on a foam pad or backpack.
