Cercedilla Field Notes: Linchen

Today, the first day of Spring of 2026, was unfortunately cloudy and raining all day, but fortunately this afternoon there was a pause in the rain and we were able to take a walk to the Ermita de San Antonio. Possibly due to the sky being grey and our attention not bound to the horizon, we noticed that all the rocks are cover in splotches of all sorts of different colors. My wife commented that it was because the rocks in the the Sierra around Madrid have a lot of granite (correct) and I said I thought that it was due to lichen (also correct). Read on for what I learned once we got home and I began investigating!

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Ersa Crash Postmortem

That was exciting! Yesterday morning I was having saturday morning coffee in bed doing a bit of prompt driven development to add weather predictions to my Remarkable sleep screen when suddenly weird things started happing on Ersa, a Raspberry Pi 4 Model B that hosts everything in my house including this blog. By weird I mean I was trying to create a new file but said it was a read only file system. I figured I had run out of space, but was not the case, so I opted for a “windows” solution: reboot. And that was all she wrote and Ersa did not come backup. The picture above is the open heart intervention on Ersa trying to figure out what was going on. Read on for the frantic recovery actions and a incident postmortem retrospective to ensure this learning experience leads to improvements!

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Cercedilla Field Notes: Wind

When I started the field note series I would not have imagined that one of the posts would be about “wind” but I have had an intense last 7 days thanks to the wind in Cercedilla and not for the first time so I thought it is a legitimate post from the field.
Last Monday (February 16th), as we can witness in the picture above, there were burst of winds (“Racha”) up tp 91 km/h (56 mph). I got a call from a kind neighbor (thanks Fernando!) to let me know a tree from my property had fallen and was resting on the communities telecommunication cables (fortunately not electric):

Read on for all the fun that ensued and for last years wind problems as well!

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Notes: Atlantic Meridional Overturning Circulation (AMOC)

Today I read an article that in October Iceland officially classified the failure of the Atlantic meridional overturning circulation (AMOC) as a national security risk. If the AMOC were to fail, temperatures in Iceland could plunge to -50º Farenheit and would glacier over.

I first heard about the AMOC in the highly recommendable book “A Short History of Nearly Everything” by Bill Bryson. From what I remember is that he said: look at where England is and then trace on a globe to see where that lines up at on North America. Why is one a tundra and the other highly populated? AMOC.

Read on to see my notes on AMOC.

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Flipper 101 Uses

A while ago I saw a post where this guy did 50 different things with his Software Defined Radio (SDR) and I thought it was a really great idea to push something to the limit and explore it fully. So I have been wanting to do the same for my Flipper Zero, a “caprichho” (an extravagance or something I really did not need) that I bought over a year ago, and had fallen into the what I had seen people claiming on the internet: they were only using it as an over priced replacement for a remote control.
Unfortunately when I started this post and before researching my faulty memory remembered it as 101 things to do with SDR but in fact it was 50, but I already had started the post and although I almost certainly will set myself up for failure, but I will leave it at 101 uses for a Flipper!
The only caveat is that I will post this today (01/02/2026) with the tests I have done so far, and continue to add more as I go, updating this time stamp every time I add something: last update 04/03/2026.
Read on what will surely go down as my opus magnum!

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