How to See a Cloud Inversion in Boulder

What is a Cloud Inversion?

We won’t get too deep into the science, but, in a nutshell, a cloud inversion is the visible manifestation of a temperature inversion. Typically, in the Earth’s lower atmosphere — the troposphere — air gets colder as altitude increases (why mountain tops are cooler than valleys), but a temperature inversion flips this — a layer of cold, dense air gets trapped at ground level beneath a layer of warmer, less-dense air. This warmer air prevents the cooler air from rising, and when the cooler air is humid enough...and the temperature is just right...the magic happens! A thick layer of fog or mist forms, creating a cloud inversion.

How to Predict an Inversion

Although there’s an undeniable element of luck to catching a cloud inversion, if you watch out for a few key meteorological signs, you might be able to up your chances of being in the right place at the right time.

1. A high-pressure system: Fair, calm weather with clear skies. Although you need a barometer to measure atmospheric pressure, it’s the 21st century, and of course… there’s an app for that. Check out the Barometric Pressure website or app. “High” pressure in Boulder is typically above 30.2 inHg. If you’re old school and watch the weather on the news, high-pressure systems are typically marked with a blue H on weather maps.
2. Clear, calm nights: A cloudless sky along with little wind.
3. Recent moisture: Chances of an inversion happening increase after rain or snow, which creates moisture in the low-level air by saturating the ground.
4. Temperature and dew-point convergence: Possibly the most critical factor, if the overnight low is close to or below the dew point, it is much more likely that an inversion will occur. (If you need a refresher from second-grade science class, the dew point is the temperature at which air becomes so saturated with water vapor that it starts to condense into liquid, meaning the air can no longer hold all its moisture in a gaseous state.)

Best Seasons

Prime seasons for cloud inversions in Boulder are late fall, winter and early spring.

Best Time of Day

Sunrise. As the sun gets higher, the ground and trapped air warm, too. The cloud layer typically burns off within a few hours of sunrise, although on occasion, Boulder will be “socked in” with an inversion for most of the day.

If you're more of a play-it-by-ear person, you can always pop up Flagstaff Road, which is only a 10-minute drive from downtown, when you see the conditions lining up just right. One of the perks of Boulder is that you're never too far from the mountains.

Top Inversion Viewpoints in Boulder

Don’t be discouraged if conditions are foggy. Keep slowly, carefully ascending until the fog thins and the sky brightens. Before you know it, you’ll be above the clouds and in a whole new, serene, blissful world.

Flagstaff Mountain

There are multiple possible lookout points on Flagstaff. This mountain is the most popular and accessible destination for panoramic viewpoints. Its windy road will lead you all the way to the top to its nearly 7,000-foot summit.

Panorama Point Located about a half mile up Flagstaff Road, you can drive right up to this overlook for sweeping eastern views, ideal for sunrises. This is a bit lower in elevation, so if it is shrouded in clouds, you’ll want to continue driving up Flagstaff Road to Lost Gulch Overlook for a higher elevation.

Lost Gulch Overlook Another three miles or so up Flagstaff Road, this highly photographed western viewpoint faces the snow-capped Indian Peaks Wilderness. Since it looks out over a very different type of landscape, chances are you will find some interesting vantage points here if you’d like to explore a little deeper into the inversion.
 

National Center for Atmospheric Research (NCAR)

For lower-lying inversions, trails (and even just the parking lot) at NCAR make viewing a cloud inversion quite simple. You can park for free at the NCAR Mesa Laboratory and wander around the mellow nearby trails to experience the inversion in a gorgeous natural setting. The accssible NCAR Trail is a well-paved, gentle, one-mile loop.

Green Mountain

At an elevation of 8,144 feet, if you want to get even higher above the inversion, Green Mountain is the place to do it. The stunning summit offers a 360-degree panoramic vista. Although it’s only accessible via hiking, this strenuous undertaking will be hugely rewarding for the adventurous folks who are prepared for a difficult hike with likely cold, wet conditions.

Mount Sanitas

You’ll feel like shouting, “I’m king of the world” from the summit of this lung-busting hike. It's one of Boulder’s most popular, but chances are there will be fewer folks out before sunrise... in the fog... attempting to catch a cloud inversion... you psycho! (We mean that in the most loving way possible.) Although we can almost guarantee you'll run into at least a few (fellow psycho) Boulderites attempting to bask in some of that inversion magic.

Bear Peak

As Boulder's second-tallest peak at 8,461 feet high, seeing Longs Peak from this summit makes for epic cloud immersion viewing. Bear Peak is a serious mountain climb (so prepare accordingly), yet it is accessed right within Boulder’s city limits for those early morning, last-minute adventures.