After a late-summer storm, the mountains of Upstate South Carolina can put on a show that lasts only a few minutes.

There are evenings in the South Carolina Upstate when the mountains seem to make their own weather.

A small late-summer storm had passed through when the scene in the photo above began to develop. The rain was over. The sun was dropping toward the horizon. Instead of clearing completely, however, bands of low clouds remained wrapped around the mountains.

Closer to the ground, little wisps of mist appeared among the trees. In the distance, entire sections of the mountains disappeared behind clouds while the higher ridges remained visible above them.

For a few minutes, the familiar landscape looked completely different.

It may look unusual, but there is a good reason the mountains sometimes seem to wear the clouds.

Why Do Clouds Hug the Mountains?

Mountains don’t just sit underneath the weather. They help create it.

When moist air encounters a mountain, the terrain can force that air upward. As the air rises, it expands and cools. If it cools enough to reach the point where the air becomes saturated, some of its water vapor condenses into tiny droplets and a cloud forms.

Meteorologists call this orographic lifting. The National Weather Service describes it as air being forced to rise and cool because of hills or mountains. When enough cooling occurs, water vapor condenses into clouds.

That helps explain why clouds can appear to cling to a mountainside instead of floating high above it.

The mountain is actually helping create the conditions that allow the cloud to exist.

A Summer Storm Adds Even More Moisture

Now add a late-summer rainstorm.

The air in Upstate South Carolina is already capable of holding a tremendous amount of moisture during the warm months. A passing storm wets the trees, leaves, soil and surrounding vegetation while leaving plenty of moisture in the lower atmosphere.

Then the storm moves away.

As evening approaches, temperatures begin to fall. Air that was warm enough to hold all that water vapor begins cooling closer to its dew point. In the right conditions, condensation begins near the ground and along the mountains.

That’s when the landscape can suddenly fill with mist and low clouds.

The National Park Service describes a similar process in the southern Appalachians, where warm, moist air rises along the mountains, cools and forms clouds. The region’s dense forests also contribute water vapor to an already humid environment.

Is the Forest Really “Steaming”?

Look closely at the lower portion of the photograph, and there are several small plumes rising above the trees.

They almost look like tiny fires.

They’re not.

What looks like smoke or steam is essentially very localized mist or cloud forming near the wet landscape. After rain, plenty of moisture is available near the surface. When that humid air cools enough, tiny suspended water droplets become visible.

The effect can be especially dramatic in hollows and other low areas where moist air collects.

It is the same basic reason fog is really just a cloud at ground level.

From a distance, though, watching those individual patches appear among thousands of acres of forest makes it look as though the mountains themselves are steaming after the rain.

Why Some Ridges Disappear While Others Don’t

One of the most interesting parts of this kind of evening is that the clouds aren’t necessarily covering everything.

One ridge may be completely visible.

Another may disappear halfway up.

A higher summit might stick above the clouds altogether.

That’s because temperature, elevation, moisture, and airflow vary throughout mountainous terrain. The height where the air becomes saturated can intersect one slope while sitting below the top of another.

The result is the layered appearance visible after some storms: forest in the foreground, mist in the valleys, clouds wrapped around the slopes, and mountain summits emerging above them.

The National Weather Service notes that variable terrain can produce dramatic differences in fog and cloud cover as cooler, moist air settles into valleys and approaches saturation.

Then the Sun Comes Out

The clouds alone would make an interesting scene.

Sunset changes everything.

When the storm moves far enough away to expose the western horizon, the setting sun can shine underneath or through the remaining clouds. The low angle of the sunlight gives the scene its warm gold and orange tones while the mountains remain dark.

Mist closer to the ground catches that light.

Suddenly, little patches that might have been almost invisible during the middle of the day begin glowing against the forest.

It can happen quickly.

Ten minutes earlier, the mountains may have been hidden by rain. A short time later, the clouds can lift or dissipate, and the entire scene is gone.

That short window between storm and sunset is what makes evenings like this special.

Is This the Famous Blue Ridge “Haze”?

Not exactly.

The clouds and mist visible in this photograph are made of tiny water droplets, but the famous bluish appearance of the Blue Ridge Mountains has another contributor.

Forests naturally release volatile organic compounds. Those compounds can contribute to tiny airborne particles that scatter light and help produce the characteristic blue appearance associated with the mountains. The National Park Service notes that natural emissions from the region’s forests help create the Blue Ridge’s distinctive haze.

So we tend to lump several different things together as “haze.”

There is distant atmospheric haze.

There is fog.

There are low clouds.

And then there are evenings like this one when several layers of moisture can appear across the landscape at the same time.

The Best Time to Watch for It

There is no guarantee you’ll see this exact combination, which is part of the fun.

But if a summer storm passes through the Upstate late in the afternoon, don’t assume the show is over when the rain stops.

Look toward the mountains.

An especially promising setup is a warm and humid day followed by an afternoon or early-evening shower or thunderstorm. If the storm begins moving away before sunset and the western sky starts clearing, conditions can become interesting very quickly.

Low areas may begin filling with mist. Clouds may remain caught against the ridges. If the sun finds an opening near the horizon, the entire scene can light up.

Sometimes the best mountain view isn’t on a perfectly clear day.

It’s the few minutes immediately after the storm.

A Landscape That Never Looks Quite the Same

That’s one of the best things about living near the Blue Ridge foothills.

The mountains are always there, but they rarely look exactly the same.

Morning fog can hide them completely. A clear winter day can reveal ridges far into the distance. Summer haze can turn them blue. Thunderstorms can erase them in minutes.

And every once in a while, after the rain moves on and the sun starts going down, the clouds settle into just the right places.

The valleys begin to steam.

The ridges disappear into white clouds.

The sun slips through one last opening.

And for a few minutes, the mountains seem to breathe.