June 11, 2013


Filed under: Geology, Hiking, North Cascades, Weather — geezerwriter @ 8:00 pm
Hidden Creek

Hidden Creek

Last Thursday an even dozen of us geezers made the long drive down through Skagit County, despite the risk of being caught up in the traffic due to the the recent collapse of the I-5 bridge over the Skagit River, around to the east side of Mount Baker and all the way up to the top of Baker Lake to hike the East Bank Trail as far as the mouth of Noisy Creek. It is a wonderful hike through an old growth forest above the shore of Baker Lake, about 10 miles round trip with roughly 1000 feet of ups and downs along the way – not usually enough to justify a 140 mile round trip drive, but we are getting pretty tired of hiking on the coast and eager to get into the mountains. This area is less than 1000 feet above sea level so the winter snows, if there were any, are long gone.

(You can read more about the hike on my friend DJan’s blog D-Jan-ity.)

But there was plenty of snow on the high ridge above us, as evidenced by the roaring meltwaters in Hidden Creek, which we crossed about halfway along. That smokiness in the background is not fog or mist, since it was warm, dry day – it is all spray from the creek. We had to shout to be heard over the waters’ roar while standing on the bridge, and this isn’t even the one they call Noisy Creek!

A few months ago I blew part of my daughter’s inheritance on a new camera and I’ve been meaning to publish some of its pictures and describe its cool features, but for now I’ll just show a couple. The main reason I bought the new Sony RX-100 is that it has a larger light sensor than most point-and-shoot cameras, making for less “noisy” pictures. When one crams a whole lot of pixels into a tiny sensor, the electrons can “leak” from on pixel to another, giving a messy, smeared effect especially in low light situations. The larger sensor will allow me fewer excuses – on another day I will show off more of its abilities.

The picture above is cropped from a vertical, about 30% of the original. It is not a great picture but it shows pretty good color rendition in low light.

At our destination we enjoyed a splendid view of Mount Baker including as a special treat a substantial cloud of steam from the crater.

Baker from Noisy Camp

Baker from Noisy Camp

The crater is that notch between the two peaks (named for Generals Sherman and Grant). It is always giving off steam but it is often obscured by other cloudiness or blown away by strong winds. It is my understanding that the steam does not come directly out of the volcano, but results from the ever-present snow at that altitude melting and seeping down into cracks until it is boiled off by the hot magma that lies below the surface.

And that picture is not a great one, either, but it is an example of one of the new camera’s many fancy tricks – it automatically noticed that it was an extremely high contrast situation, from the hikers in the deep shade on the beach to the snow on Baker. In a single image either the hikers would be black silhouettes or the mountain would washed out to bone white. This camera, without being asked, took three quick pictures at different exposures and blended them into one. This is called High Dynamic Range (HDR) processing and has been available as a post-process after the images are uploaded to the computer but this gadget does it on the fly.

More Noises

Baker River GPS error

Baker River GPS error

Near the end of the hike, as we approached the trailhead, I glanced at my GPS and noticed that it was indicating that we were quite far from the track that it had it had recorded in the morning. I was pretty sure there weren’t two trails! And sure enough, when we got back on to the earlier track there was no second trail and no sharp turn. The picture on the right (you can click to enlarge it) shows a number of tracks from previous times we had hiked this trail all looking roughly the same and the new one, in bright red, following along with the others but then turning sharply to the right and bouncing around a bit before resuming a northeasterly course roughly parallel to the true one. It even shows us going well out into the river (I think we would have noticed that!) before getting its act together at the bridge.

Hoypus Hokum

Hoypus Hokum

Now I don’t watch the GPS all the time, but I had noticed in the morning that it was showing an accuracy of about 30 feet. However that spurious track is a couple of hundred feet from the true one. We were in a pretty deep valley but it was a clear day in a light forest and all the rest of the track looks pretty normal.

And this is not the first time I’ve seen this sort of thing. Last year (or was it two?) we were hiking at Hoypus Hill in Deception Pass State Park on another clear, dry day (water, in clouds or on trees, can absorb radio waves and interfere with GPS reception), in light forest cover but this time on the top of a hill with no mountains blocking the sky (another potential GPS vexer) and I got the track shown in red on the map to the left. It has roughly the same S-shape – it even flattens out for a while near the middle of the S – but veers way off from the true track. . And it eventually drifted  back “on track.”

Cub Creek Crud

Cub Creek Crud

And then there was the time on the Cub Creek hike on Stewart Mountain east of Bellingham – again a bright, clear day, near the top of the mountain with a hill on one side blocking some sky but not much. And this time we were walking on a level road so the tree cover was minimal and the true track was right there on the map on the GPS device. We were proceeding east-to-west when the track veered off, again keeping the same general shape – notice that there is a small, gentle inflection about halfway along that shows on both tracks. In this case the red track takes a sudden screeching turn to the left and zips back to the road.

What gives?

So how is this possible? The GPS knows nothing about its direction of travel (I usually have the compass feature turned off since it eats a lot of battery time) or the shape of the trails – it just receives signals from a number of satellites that allow it to triangulate its location. It is supposed to know where it is at any time, but that’s all. And if the signals are weak or otherwise inadequate the device will show that by raising the “accuracy” distance or just bailing out entirely. In these cases it appears that the device was still receiving signals that were good enough and consistent enough to allow it work through its algorithms and come up with what appeared to be a “good” answer. And they were good enough to get the overall shape of track correct.

The Explanation ? ? ?

I was musing about this with DJan at the end of the Baker Lake hike and I remembered that at the time of the Hoypus Hill hike someone (probably DJan herself) had mentioned that we were in a period of high sunspot and solar storm activity.  And she said that that was true again now! I know almost nothing about such things but I poked around a little on the Interwebs and confirmed high activity on Thursday and higher yet on the Hoypus Hill day; Cub Creek was middling, but definitely not low.

Again, I have no idea how solar storms could do this, but a burst of radio frequency noise could conceivably fit with the notion of a widespread but temporary disruption of radio signals – after all those satellites are way up where the solar wind could get at them.

But still this is deeply weird. The only lesson that one can surely take away from this is to be very careful about trusting a GPS device. They work very well most of the time but you should always be looking for the possibility of error.


1 Comment »

  1. That is a wonderful picture of Baker and our lunch spot, Al. My camera doesn’t give me anything nearly as cool, but then again, it didn’t cost an arm and a leg, either. However, if something were to happen to my camera, I would be very very tempted… 🙂

    Comment by DJan — June 12, 2013 @ 5:47 am

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