Fresh snow and winter fog glow in the early morning light.
The large storm from the first weekend in December finally passed and left a week of contrasting weather. There was a striking difference in conditions north and south of Black Butte Summit. That line held pretty firmly most of the week, dividing the southern area where sunshine abounded with the area to the north, where a dense, frigid fog filled the Shasta Valley and lapped at the flanks of Mount Shasta. When the fog finally receded, it was a glorious retreat and it left some of the most striking and beautiful rime ice conditions I have seen around Mount Shasta in a long time.
Before getting to the rime ice, it is worth accounting for the conditions at the end of the storm. Suffice to say, it snowed a lot and by the time it was done, there was over 2 feet of snow at my house. The final, large deposit left about 15 inches and it was a wet snow with high water content. That is exactly the kind of snow we need but it made for miserable clearing. Despite this, it was beautiful.
Before the storm.
After the first pass.
After the storm.
The snow was certainly copious. I had to clear my house and the cabin across the street, since we were hosting our clinic’s Christmas party there that night. I had my work cut out for me…
By the time I was done, not only did it feel like the Christmas season, it really looked like the Christmas season!
On Mount Shasta, the conditions were lush. The snow blew around the mountain in flurries and the dense blanket of snow glowed in the light of the rising sun.
It had been a long time since the mountain had been this white. Last winter the snow was dry and powdery and never seemed to accumulate, just blowing away right after it had been laid down. This snow was different. It was thick and sloppy and clung to the mountain and the trees in the cold temperatures.
On Black Butte Summit, which is roughly the divide between the Sacramento and Klamath River watersheds, the conditions were a bit different. A heavy fog had set in on the north side of the pass and filled the Shasta Valley. At the pass, however, the fog was perpetually breaking up and sailing past Mount Shasta like small clouds. In the mornings, it proved to be a pretty sight, as the wisps of fog caught the light of the rising sun.
While snow drifts cover parts of Black Butte but the trees were frozen in rime ice.
It was as the fog gradually retreated that the unusual artistry of the season was revealed. The first place where it was obvious was on Black Butte. In addition to accumulated snow drifts, rime ice covered the the rocky crags and trees. Rime ice forms when freezing conditions (usually really cold, not just when temperatures hover around freezing) persist and water from clouds or fog freeze onto objects. Typically it is manifest on things that will stick up into the fog or cloud and catch the passing water. Black Butte, being a prominent landmark on the pass, and with the trees and rocks adding added prominence, is regularly the recipient of a lot of rime ice. However, it tends to be hard rime ice, which forms in really windy conditions so the ice tends to collect on one side of a tree or rock and forms solid icy layers. Soft rime ice is more unusual and it was this form that was revealed as the fog dissipated to the north.
Rime ice, not snow, covers the trees north of Black Butte.
As the fogged backed away, a spellbinding winter world was revealed. Soft rime ice covered everything. The trees were white, but it was a crystalline paleness that came from ice on the needles, not snow. The white ice was readily contrasted green trees that the morning light really highlighted.
The dense fog had hung around for a few days, so when, on Thursday afternoon it finally lifted in Weed, I headed up there to catch the sunset and was able to get there just in time to see the last light fade out on the mountain. The alpenglow really stood out against the white, white world of the rime ice.
The icy structures covered everything and it was obvious that the formations were delicate and exquisite. This was rime ice of a different nature to that which normally forms on Black Butte. This was soft rime ice. This forms in the same way as hard rime, except that the conditions are not windy and are quite still. This allows the water droplets to form their own structures as they freeze, rather than be sculpted by the wind. The end result is a kind of miniature icicle. Collectively, the soft rime looks like ice thorns. There was no question in my mind that I would need to come back in the morning to really get a better look it in the light.
Heading out the next morning, I thought that perhaps I might head to Truchas Ridge to see the ice formations there. Though the fog had cleared at higher elevation along the pass near Black Butte and Weed, deep in the Shasta Valley, the fog persisted.
I headed out to the ridge anyway but it was still oppressively foggy. It was also a bit warmer and had less ice formations. I promptly headed back north to the rime ice zone. What I found was spectacular.
It seemed like the entire world was covered in miniature penitentes. Icy thorns had grown off of anything cold enough to support them. For those driving by, the soft rime blended together, and things almost looked like they had just been snowed on. It was easy to miss the incredible spectacle that was found throughout the area. No doubt this has happened before, but I had never seen such a parade of algific forms.
As the sun climbed higher in the sky, the world seemed to glow. It was as if the soft rime was meant to strain light out of the air, just as the trees had strained freezing water out of the fog. It was a glorious, unforgettable sight. With warming temperatures and perhaps even rain on the horizon, it is not something that is meant to last but for a fleeting moment in time, the world was a flame with thorns of ice.