Sciency Thoughts: Sport

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Wednesday, 29 December 2021

Surfer killed by shark off the coast of Morro Bay, California.

A surfer has died after being attacked by a Shark off the coast of the town of Morro Bay, in San Louis Opisbo County, California, on Friday 24 December 2021. The body of the 31-year-old man, whose identity has not been identified, was recovered after fellow surfer Rebecca Frimmer of Morro Bay found his board floating off the town, then discovered he was still attached. Despite attempts at resuscitation, the surfer was declared dead at the scene, with injuries described as severe enough that it was unlikely he was alive when found. The attack is thought to have been carried out by a Great White, the only large species of Shark found in the area.

Sign warining of the danger of Shark attacks, following a fatal incident off the coast of Morro Bay, California, on Christmas Eve 2021. San Luis Obispo Tribune.

Despite their fearsome reputation, attacks by Sharks are relatively rare, and most attacks on Humans by Great White Sharks are thought to be mistakes. The species feeds principally on Marine Mammals, which we superficially resemble when we enter the water, gaining the majority of their nutrition from the thick adipose (fat) layers of these animals, which we lack. Due to this, when Great Whites do attack Humans these attacks are often broken off without the victim being consumed. Such attacks frequently result in severe injuries, but are seldom immediately fatal, with victims likely to survive if they receive immediate medical attention.

The Morro Bay area has had two other recorded Shark attacks in the past decade, one in 2015 and one in 2019, both on surfers, neither of which was fatal. The area is home to a population of Great White Sharks, which are being studied by scientists from the Marine Science Conservation Institute, and which is believed to have grown in recent years, due to an increased number of Elephant Seals breeding on the coast.

Tuesday, 28 December 2021

Avalanche kills skier in Colorado.

A skier has died following an avalanche at Cameron Pass in Colorado on Friday 24 December 2021, according to the Colorado Avalanche Information Center. The skier, who has not yet been named, was with a companion when he was buried by the event, and despite being dug out promptly, did not survive. The avalanche was about 50 m wide, and is thought to have been caused by the failure of a layer of faceted snow 30-100 cm beneath the surface at a point where the slope steepens sharply. This had been covered by a recent snowfall, and would not have been apparent to the skiers. This is the first fatality of the 2021-22 ski season in Colorado; twelve people are thought to have died in avalanches in Colorado in the winter of 2020-21, the majority of them while skiing.

The crown of the 24 December 2021 Cameron Pass avalanche. Lucas Mouttet/Colorado Avalanche Information Center.

Avalanches are caused by the mechanical failure of snowpacks; essentially when the weight of the snow above a certain point exceeds the carrying capacity of the snow at that point to support its weight. This can happen for two reasons, because more snow falls upslope, causing the weight to rise, or because snow begins to melt downslope, causing the carrying capacity to fall. Avalanches may also be triggered by other events, such as Earthquakes or rockfalls. Contrary to what is often seen in films and on television, avalanches are not usually triggered by loud noises. Because snow forms layers, with each layer typically occurring due to a different snowfall, and having different physical properties, multiple avalanches can occur at the same spot, with the failure of a weaker layer losing to the loss of the snow above it, but other layers below left in place - to potentially fail later.