Monday, December 9, 2019

The Week's Next Surprise: River Otters on the Tuolumne

It's not like I haven't seen them before. I see River Otters once every few months on the Tuolumne River adjacent to the trail I follow on most free mornings. But until this week, I've never caught any getting out of the river. They've always been swimming. But this morning a pair of otters were searching and playing along the river just downstream of the trailhead. I sat and watched them swim for awhile and then they climbed up on the branches of the river thickets.

I tried a couple of videos, but only one came out well. It's a little bit shaky because I was at total zoom, around 60x, but they came out pretty clear. It's been a week of little nature surprises, with foxes and rare birds and the like. Otters always give me a reason to smile a bit in the midst of lots of challenges.

Sunday, December 8, 2019

The Day I Found I Could See Half Dome and El Capitan From Near My House And Why it Was So Hard To Do So

Can you pick out Half Dome in the picture above? It's not easy...
Anyone who follows my other blog (Geotripper's California Birds) knows that I walk the Tuolumne Parkway Trail just about every time I have a free morning, watching for birds and getting exercise. Unfortunately, given the air quality of the Great Valley where I live, I cannot see the source of the Tuolumne River, even though the mountain crest is only 40 miles or so away. But once in awhile a storm blows through, and I am reminded again that I live next to one of the world's great mountain ranges. That happened this week as our first major storms of the season passed through, dropping more than three inches of rain locally, and several feet of snow on the very dry mountains above. The Tuolumne Parkway Trail climbs to the top of the bluff above the river to pass around the water treatment plant, and provides a nice view of the Sierra Nevada crest. I was impressed enough to snap some pictures. 

Later on, while looking at the pictures, I saw what looked like a familiar ridge-top. I consulted with Cal Topo, and by golly, I was right. I had captured a picture of Half Dome, and El Capitan right in front of it! It's not an obvious view, and you would need binoculars or a telescope to see it (or the zoom on my camera), but it's there. I had never noticed it before from this vantage point because both rocks get swallowed up in the rocky ridges behind (the peaks behind Half Dome are half a mile higher in elevation). The snow from two days earlier helped to highlight the summits of both Half Dome and El Capitan. The view of Half Dome from the valley floor is more obvious from other angles, even though the concept that it can be seen at all has been contentious at times...

Can you see it in the picture above? It's a challenge. Give it a shot and then consult the CalTopo wireframe below to see the identity of the peaks in the picture...

Zooming in and centering the two rocks makes them just a small bit more obvious, but it is still hard to see, given that we are only seeing the topmost parts of both Half Dome and El Capitan

Zooming in even more, the summit of Half Dome is even more obvious.

I've annotated the photo to help out a little...
They are from much closer and from a different angle, but the webcams in Yosemite Valley provide an idea on the snow pattern on Half Dome on the day I saw it from the Central Valley.

If you have a small bit of a wild place somewhere near where you live, visit as often as you can. You never know when a new discovery or surprise will be waiting. This week alone, I saw a beautiful Gray Fox in the wild corner of my campus, and a wildly out of place bird a few feet from where I took the pictures of Half Dome.

Tuesday, December 3, 2019

Why I Always Have a Camera: Our Campus Gray Fox

There is a reason I have a camera every time I go walking. I might not see something interesting every time I head outside, but when something interesting appears, I want to have a camera handy. Today I almost broke my own rule. I'm usually looking for bird species, and the day was dismal and gray, poor conditions for getting any kind of decent pictures. But on a whim I changed my usual route, and went north to check out the second sheep compound.
I first saw it hidden partly behind a fence, and all I could see were some ears and a gray-colored body that reminded me of a Great Horned Owl. But when it didn't retreat, I could see that it was a Gray Fox (Urocyon cinereoargenteus). I was thrilled! The Gray Fox is native to our region, and the more commonly seen Red Foxes are not. These may be the best pictures I've ever captured of the fox.
The Gray Fox is found all over North America, and has been part of the ecosystem for at least the last 3-4 million years. There are a large number of regional subspecies, and a closely related species, the Island Fox, found on the Channel Islands off the coast of the state. The development of agriculture in the Great Valley of Central California destroyed 95% of the original habitat for the foxes and the many other native species. Gray Foxes are adaptable, though, and have often done well in the vicinity of human habitations. There is a richness of rodents in the vicinity of our agricultural developments on campus that provide the foxes with a secure food supply. I've seen them on numerous occasions, but they rare stick around long enough for pictures. Today was a lucky day...

Sunday, November 24, 2019

Travels in Cascadia: Deserts in Canada...and What's with this Lake??

Did you know there is a desert in western Canada, in British Columbia? Well, okay not quite a desert by any standard we have down here in California and the southwestern United States, but it is a distinctly sub-arid region in a part of the continent better known for temperate rainforests. And we Californians tend to think of any place beyond the 49th parallel as an Arctic wasteland of tundra and Polar Bears. So it was a surprise as we left the alpine landscapes of Whistler and Pemberton to enter into sagebrush country and distinctly warmer weather. We were in the Okanagan Valley, on the verge of returning to the United States.
I had heard of an unusual lake to be found in the hills above the Okanagan Valley that would be a pretty handy mystery for our students, and which had a nice connection for our anthropology majors. The only problem was wondering if it would be dry or not.
Dry? Doesn't that defeat the meaning of lake? In most places, of course. But we are talking deserts here, or at least sub-arid landscapes, and yet a landscape that was sculpted by the massive continental glaciers that once covered all of Canada and 30% of the United States. Glaciers scour out all kinds of undrained depressions and blind valleys, so lakes are common. But if they don't have enough precipitation, they will dry up, and that is often the case with the lake we were seeking out that day. And as it turned out, it had been a wet year, and the lake was full of water when we arrived, and so the mystery was not quite as vivid. But there it was...

What are those weird circles in the water??
The lake has a totally different appearance in dry's one of the strangest sights I've never seen!
Source: Provenance is not clear...if this is your photo please let me know for proper attribution.

So what the heck is going on here? I will let you know below in case you want to think about it for a minute...
Source: Provenance is not clear, if this is your photo, please let me know for proper attribution

The answer is....I don't particularly know. Well, I know some things. The lake is in an endorheic basin, and as such does not receive enough precipitation to fill the basin it occupies. Thus it dries up rather than flowing through an outlet. The drying concentrates the soluble minerals in the water. The mineral deposits are primarily magnesium sulfates (the mineral epsomite) along with calcium sulfate (gypsum), and sodium sulfate (mirabilite or thenardite). The source of the sulfates are copper minerals in the surrounding hills. Magnesium is provided by local dolomite exposures.

What I admit to not understanding is the formation of the circles and pools. The boundaries of the circles is a dark organic rich mud that develops an efflorescence of white crystals when dry. I wonder if the circles are related to periglacial processes related to frigid conditions in winter, and I would dearly love to be educated about this!

The epsomite has been mined at times a century ago, but the lake is sacred to the local indigenous First Nations people, the Okanagan Syilx. They came into ownership of the lake in 2001, and for the time being it can only be observed from the hills above on the highway, which is reasonable. One can imagine the damage that could be done by unfettered visits of ignorant tourists. The "European" name of the pond is Spotted Lake, but it has been known for centuries by the Syilx as Kliluk Lake.

Saturday, November 16, 2019

Why did the Road Cross the San Andreas Fault? 17 Years of Geologic Change (a new Update)

I've been leading geology field studies trips to lots of places in the American West for 30 years and started to take digital pictures in 2001. I sometimes struggle to find new things to photograph when I visit a place for the 30th time, but in some cases it is not a problem. There are geologic changes that happen on a yearly basis, and with seventeen years of photos, the changes become obvious. This is a continuing update from a post in 2013, and I'll probably continue updating for the foreseeable future.
Highway 25 in the California Coast Ranges connects the town of Hollister with the access road to Pinnacles National Park (formerly Pinnacles National Monument). Along the way the highway crosses the San Andreas fault in a section where the fault creeps an inch or so each year (36°35'54.27"N, 121°11'40.19"W). Most years we've stopped to have a look at the effect the movement has on the pavement. In 2002 and 2004, the damage was obvious.
By 2008 someone had patched the road, and no fault motion was evident.
Little damage was evident in 2009 either. But by 2010 cracks had begun to appear as the fault stressed the pavement.
The fact that the fault creeps in this region is a good thing. It means that stress is not building along the fault surface, but instead is being released gradually. The sections of the fault to the north and south of the creeping section are locked by friction, and are building up the ominous stress that will eventually produce quakes with magnitudes in the range of 7.5 to 8.0. The quakes are coming and we need to be as prepared as possible.
By 2012, the road had been completely repaved, and  yet the shearing was already evident.
It became even more pronounced by 2013 and in 2014. Just by chance, the person working as a scale was the same individual as in 2004.

In 2015 the fractures were moderately larger. They'll need to start thinking of road repairs before long.
In 2016 Laura once again provided scale, as she did in 2014 and 2004.
Here in 2017, long-time trip volunteer Mary provides scale. The cracks in the road are just a bit larger, but they didn't look appreciably different than the previous year except for a twist (pun intended).

On Dec. 2, 2018, the break to my eye seems more continuous. It's now been six years since the road was completely repaved.

Last year the paint was deformed (twisted), but not split (below).
The offset paint strip reminds me of illustrations of elastic rebound theory, the idea that stress builds up on a fault line over time. In that model, the land on either side of the fault is distorted over time until the frictional resistance is overcome and the rock snaps back to its original shape. That won't be happening with the paint. Last year in 2017 I said "if they don't repair the road (as they often do; see above), it will probably show a clear break by next year." Here's what transpired:

First, a close-up on 2017's center stripe...
And here's how it looked on Sunday, Dec. 2, 2018:
As predicted, the break in the paint is complete...

And here is the new update for November 16, 2019: Long-time volunteer Paul provides scale (he has been assisting MJC with field trips for 25 years!). The crack continues to grow, and I wouldn't be surprised if it was patched by next year.
 The paint on the center strip is split even more.
November 2019
These little changes that happen at a rate visible in human lifetimes add up to huge changes when multiplied by thousands or millions of years. The nearby eroded volcano of Pinnacles National Park has been displaced 195 miles (315 kilometers) in the last 20 million years or so by movement along the San Andreas.

Monday, November 11, 2019

The Last Planetary Transit I'm Ever Likely to See: Mercury Today

The Sun shown just a bit less brightly today, not that anyone could tell. The planet Mercury passed across the disk of the Sun over the space of a few hours this morning, presumably blocking a bit of sunlight from reaching Earth. It was probably the last time I'll ever see a planetary transit.
Today's transit of Mercury (it is just above the center of the Sun's disk).
One needed some special equipment to see the event, mainly a camera or telescope with enough magnification to see the planet, and filters powerful enough to keep the observer from burning out his/her retinas. Luckily, I was able to locate the camera filter I used to observe the solar eclipse in 2017, and my camera has a 60x zoom. In the picture above, Mercury is just above the center of the Sun's disk. When I looked again about 45 minutes later, the planet had clearly moved to the right across the Solar disk (below).
Today's transit of Mercury (it is in the upper right hand quadrant of the picture).
I've seen three transits in my life, today's, Mercury in 2016, and Venus in 2012 (below). The next transit of Mercury is in 2049, when I'll be 92 years old. I may or may not be paying attention then. The next transit of Venus will take place in 2117. I don't expect to be around for that one at all. I wondered whether there would ever be a simultaneous transit of both Mercury and Venus, and it turns out that one will take place on July 26, 69,163 AD. I think I'll let that one pass...
Transit of Venus in 2012

Mercury is the smallest of our "regular" planets, and is even smaller than it appears in the photographs because it is around thirty million miles closer to us than the sun. It's actually not all that much bigger than our own Moon. The planet has been a bit of a stranger for most of time because it is hard to see in the dusk or twilight, and we've only had two space probes come close. Luckily, one of the probes has been orbiting for the last several years, so we have a treasure store of data on the planet. It was the subject of one of my very first blog posts back in 2008.

Saturday, November 9, 2019

Travels in Cascadia: Acrophobia, Glacierlets, and "Summer" in Whistler, B.C.

Inuksuk near the top of Whistler Mountain. See the note at the end of the post.
Acrophobia, the fear of heights, is an interesting phenomenon. I don't have it, I swear. I have no trouble standing on cliff edges, or climbing up in trees, or flying. Gondolas don't bother me. There are variations and subcategories though. I can stand on a high cliff and look over the edge, but I cannot abide watching someone else do it, especially my students. And I really don't like dangling.

There are lots of creepy heebie-jeebie moments in movies, like "Here's Johnny!", or "the call is coming from inside the house", but none gives me heart palpitations like the opening scene of "Cliffhanger" when Sylvester Stallone is trying to save a young women dangling from a rope over a vast chasm. She falls unfortunately, and I always drop the popcorn while covering my eyes. And then there is that first scene from "Vertical Limit", when not one, but three people fell down the cliff.

In my youth (roughly the ages 12 through 60 years) I was a regular peak bagger and rock clamberer. But I couldn't handle dangling from a rope. I only feel comfortable with solid rock or flooring under my feet. I rappelled down a cliff just once, I've never parachuted or gone hang-gliding, and rides at amusement parks that mimic the experience have never held any appeal for me.

This fact that I hate dangling is the background to today's description of our exploration of British Columbia that we undertook last summer in July. It's because I had to dangle over a cliff in order to see something I really wanted to see: a glacier from above.
Whistler Mountain from the Roundhouse Lodge at the top of the Whistler Gondola.
We were well into our trip by the time we reached the town of Whistler, BC. We had explored the Olympic Peninsula, parts of Vancouver Island, crossed the Strait of Georgia, and wandered for days in Howe Sound, the southernmost fjord on the west coast of North America. We drove there on a modern highway, much of which was stapled onto cliffs of Howe Sound. Before the highway was completed (in the 1960s) and improved and widened in the early 2000s (in preparation for the Winter Olympics of 2010), Whistler was an isolated logging community. Today it is a busy recreational center, winter and summer.

On the day we arrived in town it was a little hard to tell which season it was July and it was cold and rainy. It could hardly be anything different (under the rules of Murphy's Law) since our weather thus far had been rather nice, and I was looking forward to seeing the spectacular alpine scenery around Whistler (my previous two visits had been in poor weather as well). We had scheduled only a few activities in the morning so the students could do some exploring on their own during the long afternoon.
The Peak Express ski lift leading to the summit of Whistler Mountain
As a major winter recreation site, the mountainsides are draped with all manner of gondolas and ski lifts, as well as some incredibly long ziplines. A single ticket provided access to most of the gondolas and the ski lifts that were running in the summer, so I headed up the Whistler Gondola, with the intention of riding and walking over a glacier for the first time (I've been to Athabasca Glacier, but not over it). There was also something up there called the Cloudraker Skybridge and the Raven's Eye that sounded worth checking out.

So this is where we talk about acrophobia. I had no problem with the gondola ride at all. It's in an enclosed space with seats and a floor and all that. But when I got out at the Roundhouse Lodge at 6,069 feet, I found that I was still 1,100 feet below the summit of Whistler Mountain. And I would have to get their via...a ski lift. A spindly rickety dangling ski lift. I know all you skiers out there are used to these things, but I'm not. I don't like them. But it was the only way to get to the top of Whistler Mountain within our time constraints, so I hiked over to the base of the cliff and loaded myself onto the lift.
The Cloudraker Skybridge and Raven's Eye (on the far right). The "snow" is actually the top of a glacier.
There are a few places I've been that feel like no human should really be there. At the very bottom of a huge open-pit mine, for instance. One looks at the rocks exposed for the first time in millions or billions of years, and it just doesn't feel comfortable. Standing two feet from flowing lava. And dangling from a thin cable over a cliff of crumbling rock. It just didn't feel right. But there I was, and soon I reached the top no worse for the wear.
Walking out onto the Cloudraker Skybridge. The Raven's Eye is in the distance, upper left.

Once I was on solid ground again I felt better. I walked over to the Skybridge and crossed it several times. It didn't bother me one bit, and I had a great view down the small glacier beneath my feet. Glacier is perhaps a strong word for what this icefield was. A glacier is defined mainly as a mass of ice large enough to flow under the influence of gravity, and this one qualified, but I suspect the rate of movement is on the order of a few inches or feet per year. The term glacierlet is sometimes applied to these ice fields (most Sierra Nevada glaciers are of about this magnitude in size).
It was immediately clear that this glacier was only a shadow of its former self. On the slope far below I could make out a barren ridge surrounding a turquoise lakelet with a couple of huge boulders. This was a very young terminal moraine, so young that plants had not had a chance to grow. The glacier ended down there only a hundred or so years ago. Although there is snow in the lower reaches, the actual glacier ends today hundreds of feet above the lake.
Terminal moraine and moraine lake at the former end of the glacier at Whistler Mountain.

The true size of the glacier today can be seen in a satellite image taken in the late summer when nearly all of the snow (but not glacial ice) has melted away (below). The loss of glacial ice is a worldwide phenomena indicating that the global climate is warming. When these glaciers disappear, their loss will have serious ramifications for the regional ecosystem. The glaciers serve as a dependable year-round water source for alpine creeks, and when that disappears, so will the animals and plants that are dependent on that water. They don't have anywhere else to retreat to.
Meanwhile, I had one more challenge. As physics tells us, what goes up must come down, and I had been procrastinating, walking around the nature trails around the peak of Whistler Mountain. I was out of time, and was going to have to take the ski lift back down. I'm glad no one was with me, because I was whimpering "oh, sh*t" over and over as the ski lift chair tipped over the edge of the void.
The arete on the east side of the glacier. The ski lift went right over it.
The scenery gave me something else to concentrate on, so I snapped lots and lots of mostly useless pictures, but I did get a decent perspective on the terminal moraine and small moraine lake behind it. The turquoise color is caused by clay-sized particles suspended in the water, derived from the grinding action of the glacier on the rocks at its base. An arete is a sharp jagged ridge that divides glacial valleys. The ski lift carried me right over the top of it.

You'll all be happy to know that I gathered myself together and was not whimpering by the time I reached the bottom of the lift.
In the end, the lousy weather mostly kept me from seeing the spectacular alpine scenery that surrounds Whistler. On the other hand I was able to see a glacier up close, and learned to live with my subtle form of acrophobia.
Google Earth image of the small glacier at Whistler Mountain. The cirque is the bowl-shaped valley where the glacier originates. The skybridge traverses the upper end of the cirque.
The Inuksuk at the beginning of the post was the icon of the 2010 Winter Olympics that were held in Vancouver and Whistler. The stone men have been a part of Inuit and other Arctic cultures for thousands of years. The use of the Inuksuk at the winter games was somewhat controversial, as no Inuits ever lived within hundreds of miles of the site of the games. The local First Nations people were the Squamish and Lil'wat.

Whistler refers to the Hoary Marmots found in the region. I saw one of them at the Roundhouse Lodge when I got back from the mountain.