In one of his poems, Carl Sandburg likened fog to a cat: silent and stealthy.

Fog in the Tetons, though, is often anything but stealthy. At its showiest it's big and bold. Undulating; expanding, receding, then expanding yet again. The mountains influence its movement. Sometimes it climbs so high the towering peaks are mostly obscured. 

Like Sandburg's cat, it behaves as if it's a living being. Unlike the cat, it appears to me as some sort of restless, gargantuan life form. 

This showiest variety of Teton fog reliably appears in autumn. Recently I was fortunate enough to have two consecutive mornings with such spectacular conditions. Compositional opportunities were plentiful as the scene was constantly changing. 

I have a nearly limitless capacity to linger when the fog is behaving in this way. It's like watching a good movie with multiple plot twists; you have no idea how it's going to turn out.

SpectralAn overnight thunderstorm blankets the mountains with the season's first significant snow and leaves behind spectacular dense fog.

Grand Teton National Park, Wyoming

This time of year, if it rains late in the evening or overnight you won't need to check with the meteorologist to know you can count on foggy conditions the next morning (this occurs in the summer, too, though I've found autumn to be the most predictable season). Post-precipitation fog isn't always as dramatic as what's pictured above, but the fact that it'll be there is something you can take to the bank.

Where you are in the valley plays a part in how dense the fog will be. Once you get to know the area you'll have a good idea where to position yourself for the conditions you prefer. While the middle of a total white-out isn't conducive to making photographs, somewhere on the edges - or on the outside looking in, so to speak, can be ideal. 

Across the DecadesImmortalized by the early 1940s image Ansel Adams made from this place, the Snake River Overlook - though it appears much different many years later - remains a beautiful setting.

Grand Teton National Park, Wyoming Other months produce fog, too. Jackson Lake, the Snake River, the lakes nestled at the base of the mountains, and the Gros Ventre River are just some of the many water sources in the area. In the winter and spring, the air temperature in the valley can be much colder than the water. Voilà! Morning fog.

The image below, made in early July, is typical of summer fog in terms of its character: it tends to be more like a blanket then - flatter and hovering over the water, leaving the peaks in full view. This day was unusual in that the fog waited until well after sunrise to fully develop, which was just about perfect since by then cloud cover began moving in from the southwest to create a more interesting combination of conditions. 

Nature's BlanketThick fog hangs over the valley beneath the Tetons as the sun rises

Grand Teton National Park, Wyoming I made the photograph below on the last day of December. The fog was very dense at sunrise; it took many hours before it began to lift and the peaks of the Cathedrals became visible. Fortunately the sun is so low in the sky at that time of year I had a lot of leeway in terms of waiting it out; harsh light wasn't an issue.

You can see how the fog eventually split with some lifting upward and morphing into stratocumulus clouds, while below a "racing stripe" persists nearer to the water.

Racing StripesBeautiful bands of low fog are suspended beneath the Teton Peaks

Grand Teton National Park, Wyoming

You never know exactly what you're going to get with fog. Sometimes it does act like a cat. Quiet. Furtive.

In Jackson Hole, though, it's often quite charismatic. Big and bold, just like the mountain range next to which it forms.

Odds and Ends

If you want to get into Yellowstone before it closes to vehicle traffic for the year, time is short; the curtain comes down on November 1st (the road between the North and Northeast entrances remains open throughout the winter). Oversnow opening is scheduled for December 15th.

In Grand Teton National Park, the inner loop (Teton Park Road) will close to vehicles between the Taggart Lake trailhead parking area and Signal Mountain, also on November 1st. There isn't a set date for the closure of the road down to Schwabacher Landing but it can be as early as Thanksgiving. Antelope Flats Road usually remains open until sometime in mid-December. After that you'll have to access Mormon Row and the barns by foot. The rest of the park remains open throughout the winter months, though be advised it will become more difficult to get around as the snow accumulates. 

It's odd to be thinking about winter road closures since it's been quite warm here for much of the month (overnight lows are about where they should be but afternoon highs have been running 10-15 degrees above average). Consequently, the trees have been confused; color in Eastern Idaho is very late. We haven't yet reached peak foliage in and around Idaho Falls. Conditions appear to be on the verge of shifting; mountain snow is predicted this weekend, with the possibility of snowfall at lower elevations also.