After a long absence due to qualifying exams and other shenanigans, I'm back to fighting crime! Well, the crime of not knowing all of this cool science. This post is branching out into a completely abiotic phenomenon that almost acts as though it's alive... and will EAT YOU ALIVE. The real-life blob attack happened more than a month back on one of the lakes of Minnesota (they have 10,000 after all, it was bound to happen). The only problem is that this blob is made up of the movie blob's one weakness! It's unstoppable! That's right, it's made of ice. Here's a terrifying video from Mille Lacs Lake that shows a giant ice sheet ruthlessly crawling onto land. It may not look like a fast advance, but if you skip from the beginning to the end of the video I guarantee you will be amazed at how far a mini-glacier can proceed in 7 minutes. What causes such a force of nature to climb right up the shore?? A few things have to fall into place during the winter and spring to bring about ice-jacking. The first part of the process is a wide enough fluctuation in temperatures over the season to cause the ice to grow towards shore. When temperatures drop far below freezing, the ice contracts and cracks form between the pieces of the sheet that pull apart from one another as they shrink. New water quickly fills the cracks and freezes to create a continuous ice cover again. If things warm up to a near freezing temperature after that, the ice expands to its original density, but with new ice formed, it no longer fits neatly over the lake! It creeps little by little up the shore every time this process repeats itself. The temperature variations are amplified if there is no thick snow cover over the ice to insulate it. But was this gradual expansion capable of causing the dramatic movement above (helpfully narrated by Minnesota accents)? No, this ice shove was probably made up of discrete chunks knows as ice floes instead of a single sheet. The secret ingredient that created the blob this past year was high winds! Gusts up to 40 mph pushed these floes in one direction across the lake and were powerful enough to keep nudging it up people's backyards. The friction they meet on land is outweighed by the force of the ice behind them piling up when the front slows down. Ice piles like this have been recorded to grow as high as 12 meters when they meet a sufficient barrier. As the immortal line at 5:55 "It's going right through their f***ing house!!" tells us, this blob means serious business as much as any B horror movie monster from outer space. These things cause tons in property damage and cannot be stopped by most of the walls mere mortals can construct. Some piers and bridges are designed to withstand the pressure of advancing ice, but lake houses and cottages don't stand a chance. Your best hope is to build your house far enough away from the shore, or do some long-term forecasting and sell it before a year like this repeats itself. As tragic as that is, the real science fiction ice-related crime is Mr. Freeze from Batman and Robin.
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Alanna DurkinExploring the realm of biologically inspired design one superhero example at a time, with some other natural sciences mixed in. Archives
September 2016
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