A Variety of Winter Weather

Flagstaff’s February weather has been very active with rain and/or snow recorded on seven days out of the first fifteen. Several days of snow on the Kachina Peaks covered the trees with a thick coating of rime ice and lots of new snow on the slopes.

Rime covered trees in the Kachina Peaks.
Rime covered trees in the Kachina Peaks.
"Flying Dutchman." It's steeper than it looks.
“Flying Dutchman.” It’s steeper than it looks.
"Allison Clay."
“Allison Clay.”
Weeds in the snow.
Weeds in the snow.

And then we had an “atmospheric river” that produced a significant amount of winter rain with about 1.5 inches falling in the Flagstaff area. The runoff in Oak Creek and its tributaries was impressive.

Pumphouse Wash—a normally dry wash—running at high volume.
Pumphouse Wash—a normally dry wash—running at high volume.
Oak Creek at Grasshopper Point: a popular swimming hole when quieter water prevails.
Oak Creek at Grasshopper Point: a popular swimming hole when quieter water prevails.

And the forecast for the next week or so is a continuation of stormy weather with lots of snow for the higher elevations. I believe the long-anticipated El Niño has finally arrived.

Comet C/2018 Y1 (Iwamoto) Moves Across the Winter Sky

Comet C/2018 Y1 Iwamoto has just made its closest approach to Earth this week. With one evening of clear skies forecasted before the next storm system moves into the area, I went out earlier this week (02/11/2019) to capture images of this fast-moving, blue-green comet. The Moon was up in the western sky with 38% of the disk illuminated. This caused considerable brightening of the sky and made it challenging to capture fine details of the comet.

Comet C/2018 Y1 (Iwamoto).
Comet C/2018 Y1 (Iwamoto).

From Universe Today:

Discovered by Japanese amateur Masayuki Iwamoto as a +12th magnitude fuzzball moving through the constellation Hydra the Water Serpent on the night of December 18th, 2018, Y1 Iwamoto is a fast mover. It’s great to see that amateur astronomers can and still do discover comets, as the robotic competition posed by automated surveys such as PanSTARRS makes such an independent discovery tough these days…

At its closest on February 13th, Comet Y1 Iwamoto will appear to move seven degrees a day. This translates into a fast apparent motion of about 2/3rds the apparent diameter of a Full Moon, every hour.

The comet was easy to find with a pair of binoculars but was not visible to the unaided eye. Its position on this evening was near enough to the bright star Regulus that I had no trouble aligning the camera.

The following image and animation show the motion of the comet during a period of just over one hour.

A one-hour composite of C/2018 Y1 (Iwamoto) showing the rapid motion of the comet.
A one-hour composite of C/2018 Y1 (Iwamoto) showing the rapid motion of the comet.

Time lapse movie showing the motion of C/2018 Y1 during a period of one hour.

Comet C/2018 Y1 Iwamoto will make its next passage through the inner solar system in 3390 AD.

A Winter Rainbow in Flagstaff

Over the weekend we had an extended period of rain in the Flagstaff area. Normally we would see snow at this time of year.—it is, after all, the middle of winter. Rainfall amounts were sufficient (1.35 inches at Flagstaff airport) to cause large increases in the flow of Oak Creek where gauges recorded a rise from ~2.4 feet (30 cfs) to 9.6 feet (6900 cfs). Other streams were running high as well.

A winter rainbow in Flagstaff.
A winter rainbow in Flagstaff.
A winter rainbow in Flagstaff.
A winter rainbow in Flagstaff.

I though it might be interesting to look at Lake Mary and Mormon Lake to see if lake levels were increasing as a result of the runoff. Indeed, they were, but not quite as much as I had hoped. Still, water rushing down Newman Canyon, a normally dry wash, into Upper Lake Mary was impressive.

Newman Canyon, a normally dry wash, is filled with runoff pouring into Upper Lake Mary.
Newman Canyon, a normally dry wash, is filled with runoff pouring into Upper Lake Mary.

Back in December 2004, we had a much bigger rain event. Lake Mary was frozen and the water rushing down the hillsides flowed across the top of the ice. The immense weight of the water caused the ice to break with thunderous booms. That is what I was hoping to experience. Didn’t happen because there was no ice this time.

Stream gauge for Oak Creek showing the rapid rise in stream flow.
Stream gauge for Oak Creek showing the rapid rise in stream flow.

My next stop was Mormon Lake. As I drove towards it the sun was able to break through the thinning clouds to my south. I took a quick look in the rear-view mirror to check for rainbows.

And, there it was. A winter rainbow in Flagstaff. Not rare, but certainly not common.

 

New Years winter storm

A band of clouds envelops the San Francisco Peaks.

A very cold storm system moved across the southwestern states on the last day of 2018 bringing snow to both the usual locations but in the lower elevations and the desert as well.

I awoke before dawn on New Years Day and was greeted with clear skies and a crescent Moon with the planets Venus and Jupiter shining brightly in the eastern sky. I drove out towards Mormon Lake anticipating great—albeit very cold—conditions for some sunrise snow photographs. On the way to the lake I encountered low clouds and patchy fog and there was nothing to be seen upon my arrival. It was already too close to sunrise to head back north or west so my only option was to wait and hope.

Clouds and fog clear away shortly after sunrise to reveal the San Francisco Peaks.
Clouds and fog clear away shortly after sunrise to reveal the San Francisco Peaks.

I missed the sunrise but about 20 to 30 minutes later the clouds cleared and the San Francisco Peaks were amazing. Low clouds and fog remained around the base of the peaks.

Rime ice glows in morning sunshine.
Rime ice glows in morning sunshine.

As the sun rose higher the side-lit rime ice on the wild grasses (i.e., weeds) at the Mormon Lake Overlook began to glisten and glow.

Temperatures were hovering in the low single digits and I was cold after standing around for about an hour. Time for breakfast and hot coffee.

The next day we hiked into West Fork Oak Creek knowing that the trail would be snow packed and there would be a dozen water crossings on ice—hopefully solid enough to support us. After several days of below freezing high temperatures and near or sub-zero overnight temperatures we were hopeful for safe ice.

Natural ice sculptures in West Fork Oak Creek.
Natural ice sculptures in West Fork Oak Creek.
There are several locations where water drips down the cliffs even at these cold temperatures resulting in wonderful icicles and bizarre ice sculptures on the ground.
West Fork Oak Creek.
West Fork Oak Creek.

We hiked to the “end” of the trail where it enters a narrow, rock-walled section of canyon often called “The Subway.” This was our turnaround spot.

Sunlight reflected off canyon walls and then reflected again on the ice.
Sunlight reflected off canyon walls and then reflected again on the ice.
West Fork Oak Creek.
West Fork Oak Creek.

On the way up the canyon we had not run into any other hikers. What a treat!

Comet 46P/Wirtanen, Rocket Launches, and Fog

I went out to the Mormon Lake Overlook early last evening (12/08/2018) to photograph a couple of different events. First was the launch of the ULA Delta IV-Heavy NROL-71 mission from Vandenburg Air Force Base. After that, I planned on pointing the camera up towards Comet 46P/Wirtanen.

Comet 46P/Wirtanen.
Comet 46P/Wirtanen.

Only part of my plans worked out. The launch was scrubbed at T-7 seconds but I didn’t know about that until much later. I just kept shooting a series of 15-seconds exposures pointed towards the western horizon and hoping that I would capture it. No launch—and there was nothing to capture.

But, wait, not so fast! It turns out there was a shallow layer of fog in the Mormon Lake basin and the series of 15-second exposures over a period of about 10 minutes resulted in a nice time-lapse movie of the fog. Unfortunately, the camera was pointed at mostly sky with very little of the ground but I’m happy with the lucky result.

Time lapse showing undulations on the top of the fog layer.
Next, I shot a series of 60-second exposures of the comet. Although the skies were cloudless, there was a lot of moisture in the air. See the discussion above about fog! The presence of this moisture and very thin fog above resulted in very colorful stars. A nice effect.

Light pollution in the night sky.
Light pollution in the night sky.

For the third act, I pointed the camera back down and over the lake basin towards Flagstaff. The fog was dissipating at this time but still shows up well. What also shows up is the large amount of light pollution in Flagstaff. Flagstaff is the worlds First International Dark Sky City but it takes a lot of work to keep the skies dark. I fear we may be losing the battle.