culture, nature, review, travel, world

Throwback Thursday: The flooding in July 2021 in Western Germany

Currently, Europe is parted into two. A line is drawn from north to south from Finland to Italy. While the regions east of the line are ruled by heat, the western half is suffering from cold.

Hot air can carry more moisture than cold air. So, the moisture comes down as rain in the area where both air masses are meeting. In addition, the high-pressure area and the low-pressure area are very stable and don’t move. Instead, the rain comes down over and over again for days in nearly the same place: in western North-Rhine Westphalia and north-west Rhineland-Palatinate, two German states near the borders to Belgium and the southern Netherlands.

After a nice start into summer end of May, the weather changed by early June. It became colder and the rain began to fall. End of June, the first extreme rain appeared here in the region. A friend of mine reported an overflooded underground car park in his newly built apartment building. Fortunately, they were able to save all cars ahead of the flooding.

Because of the constant and sometimes havier rainfalls, the lakes, rivers, and creeks were already full and the ground was already saturated with water.

Tuesday last week, the weather forecast announced another heavy rain field. For about 120-150 km long and 30-50 km wide. You can see the size in the left map below. Btw. I’m located right in the middle of the pink area. Find Düsseldorf, our state capitol, and take the letter ‘o’. Now, move up and see the horseshoe-like bend of the river Ruhr. I’m near the right side inside the area. The color indicates the amount of rain in mm per 24 hours. Up to 200 liters of water were have been falling per square meter, but no-one said to the people move their valuable belongings to higher places or even leave the area completely. The situation was recognized early enough to warn. Warnings were even sent out, but the people didn’t understand the warnings.

You can find these maps, created by Deutscher Wetter Dienst (DWD), in their official Twitter account. DWD is the official German Meteorological Service.

The next images are not mine. I got them via Facebook. It’s a city quarter of a neighboring town. This place is only about 15 km east of us as the bird flies after only a few hours of rain. The stones are the result of a landslide. It looks bad, but other areas west of us were hit even harder. You can find an article on Wikipedia with a couple of images and containing also descriptions from other affected regions.

The area west of Bonn was hit the hardest. A few smaller towns and city quarters are literally wiped away. Either, because rivers re-conquered stolen land (people built houses in riparian areas or water meadows) or by landslides when the soaked soil slipped down the hillsides. In the town of Erftstadt, we had to watch another phenomenon: in the flat area, the river Erft left the bed and flooded the fields used by farmers to grow food. Unfortunately, the ground wasn’t stable. So, the soil was washed away and left a huge and rising crate, several meters deep. This crate swallowed even complete houses while widening. The only image I found online showing this, is the header photo in this article:

https://www.faz.net/aktuell/gesellschaft/ungluecke/hochwasser-in-erftstadt-dramatische-lage-und-tote-nach-hauseinstuerzen-17440280.html

Among very few hours, creeks with usually one 30cm of water were able to grow up to several meters of water. One river with usually 60cm was reported to grow up 8 meters!!!! Despite this vast amount of water, about 24 hours later nearly all of the water was gone. Only the devastation remained. Many, many people lost everything, including their houses. About 172 are reported up to now even lost their lives here in Germany and 31 in Belgium. While 155 people in Germany are still missed. Yesterday evening the last alarms were deactivated. All the danger points are secured. Fortunately, there was no additional rain. But, many parts in the affected area still don’t have electric power, telephone, water supply, and cellular mobile telephony. Reconstruction works will last months and I guess, some people, having lost everything, will move away.

The railway company announced 600km of railways were destroyed (7 tracks) and 80 stations. No-one knows up to now how many streets and motorways are damaged or completely destroys. Not counting the pipes for water and natural gas, the wires for telephony, internet, and electric power, or the animals (wild and farm animals).

The most affected area also includes an important wine-producing area and vacation spots.

The town, where I live, wasn’t affected. First, we don’t have a river or a lake (not in town nor uphill). Second, The hills are covered with houses. So, the soil couldn’t slip away. Third, some years ago, our city government enlarged the canalization system. Luckily, it was big enough to cope with all the additional water.

I didn’t write anything about Belgium, the Netherlands, Luxemburg, and France. I’m not ignoring them. The reason is, our news didn’t broadcast much about their suffering from the flooding. So, I simply don’t know enough to write about. I only know, the Belgium area bordering the hardest hit German area was also hit very hard. I suspect the people are facing the same problems as they do here.

This last weekend. Germany was hit again: in Bavaria and Saxonia further floodings happened with similar effects as I already described.

I’m so glad for not being affected and feel very sorry for all the affected people wherever they lived. Although this isn’t the first flooding in Germany, it’s IMHO the biggest and the first (?) one in our state. I assume it won’t be the last one.

I just got the forecast for the next thunderstorm to be arriving this weekend, which is expected to hit the already pained region again. 😭

Take care!

Computer, gear, Linux, macOS, photography, review, software, technical, Windows

How to recover lost files – a software review (ad because of naming a product)

Photographers nowadays need solid IT skills for their job. How to run a computer. How to install, update and uninstall software. How to do backups. Know your operating system (Windows, MacOS, Linux) and the relevant file-systems. Each photographer hoards huge piles of valuable data (the images) on his or her computer disks. They need a strategy to recover the images after a disaster i.e. computer theft, hard disk failures or SSD corruptions (you know, each cell in flash storage has a limited lifetime because the cells die after a certain number of write cycles).  Sometimes one is faced with an empty storage card because of an unintentional re-formatting. So, what can you do?

 

The basics

First of all, be prepared! Here you can find information on how to recover such lost files. Get the necessary software now and practice with test data to know the steps when it comes to such a disaster.

In the past, Microsoft brought us FAT as the filesystem. In 1977 it appeared first in MS-DOS. Since then it was developed further and got more features. Because of the ease of organizing data (especially when it comes to sequential writes), it’s still popular for storage cards used by smartphones and cameras.

The computers itself use usually more sophisticated filesystems like NTFS, HPFS, HFS, HFS+, APFS, ext2, ext3, ext4, xfs, btrfs and more. Unfortunately, these modern filesystems are organizing data very differently to FAT and its ascendants like vFAT, exFAT or FAT32. So, recovery data from disks using one of the modern filesystems looks like a game of hazard or spinning a huge wheel of fortune where only one winning chance is set randomly. When using data recovery software you might have luck recovering recently deleted files. On FAT the chance is much higher because of the different principles the data is organized.

Now you might remember having read some reports of found data on thrown-away disks. Yes, that’s true. Forensics are able to recover the blocks of destroyed disks and scratch tiny pieces of data from the disk and reassemble it. Data is organized in blocks. The size of each block is about 512 or 2048 byte, depending on the used filesystem. For getting information like names, account data, credit card information or so, that’s enough. But, look at your images. Each image uses several MB on the disk. To recover your image, it’s a necessity to have ALL blocks and they must be in the right order. A single corrupt byte is tolerable but a couple of bytes can result in a complete loss.

In more than 20 years of handling digital photos, I never lost a complete card. But, 2 or 3 times I deleted a couple of files from the cards unintentionally. In the past, photorec was the tool of my choice. It’s an open-source tool. You can download and use it for free. But, you have to understand, how it works.

First, you have to avoid any further writings on the disk from where you want to recover data. That’s essential for successfully recover files.

 

Photorec (part of the open-source product testdisk)

The installation of photorec is easy. Linux users can install it usually by using their packet manager, while Windows users need to download it from the developer’s homepage and unpack the zip-file. MacOS users can install it via brew

$ brew install testdisk

Now you open a console (Terminal on Mac or Linux, and CMD on Windows). Next, you start photorec by telling it, where to search

MacOS / OS X

$ photorec /Volume/SD-card (or whatever name the card has)

Linux

# photorec /media/SD-card (or whatever name the card has; mountpoint also might vary i.e. /mnt/)

Windows

C:\> photorec d: (or whatever drivename the device has, where you want to recover files. Check it with the Windows Exporer)

If photorec recognizes an already started recovery, it asks you if you want to continue the session or start a new one. Next, it tries to read the directory and offers you to browse where the lost data was stored. Photorec can recover several types of data, not only jpg images. It can also recover lost partitions, if necessary. But that’s beyond the subject of this post.

When you’re fine with the position, photorec needs a location on a different disk to copy the recovered data to. After that, it only needs time.

FAT filesystems don’t delete the data on the disk when files are deleted. Instead, only the first letter of the filename in the directory is replaced by a ‘?’ which makes the file invisible and marks the occupied space as reusable. So, the magic is, photorec reads the directory and scans for filenames starting with ‘?’. Then it looks up each filename and checks based on the location information (block numbers) stored along with the filename if the relevant file is completely available (all blocks from the chain of blocks ’til the end-of-file mark). If so, the blocks are copied to the chosen target destination. But, the filename is lost. Instead, the name of the first data block, where the file was stored, is used to keep filenames unique.

As photorec runs in the console, not everyone feels skilled enough to use it.

 

Disk Drill by Cleverfiles

Recently, I got a review version of a newer data recovery software: Disk Drill by CleverFiles. It’s available for Windows and for MacOS and has a visual GUI to be handled with the mouse. On MacOS the current version needs at least the latest version of Mavericks. But older versions are also available for download, in case your MacOS is still running an older version of OS X for whatever reason. Disk Drill comes as an app to be pulled in the Applications folder only, to get installed.

I installed Disk Drill on my Macbook, which I’m also using for developing my images.

So, I have a lot of images on my disk (raw data), which I process and delete after processing them. Thus, I should have a lot of files potentially being recoverable on my disk. It’s a 512 GB SSD formated with APFS. The deep scan has run for about 40 minutes. But, as expected, Disk Drill found nearly nothing! No raw-file, no jpgs, no text documents or spreadsheets. The only files Disk Drill found were a couple of files I have had in my trash bin, which was emptied just before installing Disk Drill.

My other tests were on a disk formatted with Windows NTFS and an SDcard from my camera formatted with FAT.

Recovering files (raw data written by my digital camera) from the SDcard was very successful, just like expected. A 256 GB drive was scanned in a couple of minutes and offered tons of recoverable files.

I also run Disk Drill on a 1 TB NTFS hard disc formatted by Windows. The scan lasted nearly 3 hours while the well-equipped computer got a lot of stress and the fans run at a high level for certain times. But, I was able to work with it as usual for the whole time. In the end, the so-called deep scan found a reasonable number of recoverable files of different types. Unfortunately, all of them lost their names and were offered to me for recovery grouped by file type. Hard to find the file you accidentally deleted 😦

So, the result is not much different from the outcome of photorec.

Similar to photorec, Disk Drill also works with sessions. But, differently to photorec I was unable to make Disk Drill forget the saved session and do a re-scan after i.e. running a cleanup (I tried to wipe out some files I don’t want to be able to get recovered and check if they are unable to be recovered)

Further functions:

Disk Drill has a couple of further functions.

You can open a backup of an iOS device (as long as you know the recovery passcode) stored on your computer and recover files from iOS backup (iTunes). Works great. You can get contacts, appointments, reminders, photos, and even files.

There’s also a cleanup function. It seems it is to wipe out unused space. But, in fact, I was unable to find any result. So, I can’t say, what this function is doing.

Next, there is a function suggesting it could duplicate the boot disk, but instead it only creates a boot media similar to the recovery boot mechanism you always have on your mac. So, I have to stay with Carbon Copy Cloner for this feature.

After finishing my tests I uninstalled Disk Drill. Unfortunately, a not-quitable tool survived in the menubar. I had to dig through my applications folder and my Library folders to find where this tool resides to delete the files. After a reboot, it was finally gone!

Resume

Now it’s up to you to decide, how often you have to recover lost files and on which filesystems they are stored. I was very interested if a professional tool is better than the open-source tool. The lack of a GUI is a point against photorec. But, in my opinion (as an IT pro for more than 30 years), that’s not so dramatic. I even found the text interface much more straight forward and clearer than the GUI of Disk Drill. On the other hand, I guess, Disk Drill is even more complicated than photorec.

Nevertheless, I repeat my statement from above: be prepared for the disaster because the disaster situation isn’t a good time for such a complicated topic. Get a tool and make yourself familiar with it to avoid making a disaster situation worse.