A few days ago we had a cold front move across the area and overnight temperatures fell below freezing for a few hours in the higher terrain. It turns out that October is a good month for fog formation from these first frontal incursions. Area lakes still have relatively warm water from the recently ended summer. The passage of the cold air over the warm water allows for increased moisture flux from the warm water into the colder air that increases the dewpoint (and relative humidity) and can result in fog. Also, the shorter days–and longer nights–allows radiation fog to develop in the valleys.
With that in mind, I found myself driving past Lake Mary to Mormon Lake before sunrise on Tuesday morning. As I approached Lake Mary visibility dropped quickly to 1/4 mile, then 1/8 mile, and then 1/16 mile. Visibility improved once I passed both Lower and Upper Lake Mary. At Mormon Lake, there was fog swirling in the basin and the rising Sun was just starting to illuminate the summits of the San Francisco Peaks.
After the fog dissipated in Mormon Lake, I returned to Lake Mary where the fog was still present and I was able to capture fogbows plus a nice photo of a sailboat anchored in the lake.
Time-lapse video of the swirling fog in the Mormon Lake basin.
Time-lapse video of the swirling fog and glory in the Mormon Lake basin.
The time-lapse videos show remarkable motion of the swirling for over Mormon Lake as well as the colorful but diffuse glory that was present.
(1) Steam fog (arctic sea smoke). Steam fog forms when water vapor is added to air that is much colder, then condenses into fog. It is commonly seen as wisps of vapor emanating from the surface of water. This fog is most common in middle latitudes near lakes and rivers during autumn and early winter, when waters are still warm and colder air masses prevail.
(2) Radiation fog (ground or valley fog). Radiational cooling produces this type of fog. Under stable nighttime conditions, long-wave radiation is emitted by the ground; this cools the ground, which causes a temperature inversion. In turn, moist air near the ground cools to its dew point. Depending upon ground moisture content, moisture may evaporate into the air, raising the dew point of this stable layer, accelerating radiation fog formation.
A few days ago the waxing crescent Moon joined the planets Mercury, Venus, and Mars in the evening sky. A few clouds and the reflection of the evening sky in the lake added a bit of color to the scene.
Afterwards, I stayed around to watch the rocket launch described in the previous post.
The upside to the epic Winter we recently experienced is the tremendous amount of snow melt that filled many of the lakes across northern Arizona. Over the past several weeks we have visited several of these by car, mountain bike, running, and hiking.
This is one of my favorites. It shows Upper Lake Mary, a portion of the spillway, and Lower Lake Mary. It’s also nice that there is a nice mirror reflection of the trees in the water. This shot is only possible when both lakes are full.
Earlier we had visitied Marshall Lake. It’s not as full as it was a few years ago but considerably better than the past several years.
We did a trail run along the Arizona Trail on top of Anderson Mesa and visited Prime Lake and Vail Lake, both with lots of water.
Here are some additional images of Lake Mary taken on various days in April.
We rode our mountain bikes up Schultz Pass Road to Schultz Tank. It has been a small puddle the past two seasons but is once again full.
Finally, we did a short hike through the upper portions of Pumphouse Wash to this set of cascades.
The snow melt is done and we are now in our dry season. Lake levels and stream flows will diminish until the summer rainy season starts in July.
The North American Monsoon continues to bring convective activity to much of northern Arizona on a daily basis. There have been plenty of opportunities for colorful sunrises and sunsets as well as rainbows and even some fog.
The rainy season should continue for at least a few more weeks so there should be additional opportunities for colorful photographs.
Yesterday (12 May 2021) provided an opportunity to view the thin crescent Moon very close to the planet Venus. Also visible in the evening twilight sky was Mercury higher above the pair.
For a few months each year, it is possible to be located so that the setting of the 1-day old crescent Moon aligns along the length of Upper Lake Mary. This allows for a long fetch of water in which to get reflections of the Moon and planets. Of course, this only works if it is not windy and spring is our windy season. So it was very nice to have both clear skies and very light winds for this event.
In the above image the crescent Moon is just slightly above and to the left of Venus. Near the top center of the image is Mercury. Venus is still rising higher in the sky each day while Mercury is dropping lower. Later this month they will pass by each other with ~0.4° of separation. That should be another interesting event to photograph.