Avalanches kill four people in Colorado this week.

Four people have been killed in two separate avalanches in the state of Colorado in the past week. On Monday 1 February 2021 three skiers were killed by an avalanche at Ophir Pass near Silverton in San Juan County. They have subsequently been identified as Seth Bossung, Andy Jessen and Adam Palmer, all residents the town of Eagle in Eagle County. A fourth skier was also caught in the avalanche and buried, but onlt received minor injuries. On Thursday 4 February another Colorado man, identified as John Kuo, 41, of Vail, again in Eagle County, was caught in an avalanche in the East Vail Chutes, which was described as being about 700 m wide, and to have run downslope for about a kilometre. This brings the number of people killed by avalanches in Colorado so far this winter to eight, compared to six in the entire winter of 2019-2020.

 

Rescue workers in San Juan County, Colorado, searching for survivors after an avalanche on Monday ` February 2021. San Juan County Office of Emergency Management/Facebook.

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.

Diagrammatic representation of an avalanche, showing how layering of snow contributes to these events. Expedition Earth.

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A new species of Ankylosaurid Dinosaur from the Late Cretaceous of New Mexico.

Ankylosaurids were large, heavily armoured Ornithischian Dinosaurs, which appeared in the Early Cretaceous and persisted to the end of the period. They had bony shells comprised of fused osteoderms (bony plates that develop within the skin) that enclosed their torsos in a similar way to the shells of tortoises and turtles, but appear to have been more active, with limbs built for an upright stance and a large bony club on their tail, presumably used for defence against the large carnivores of the Cretaceous.

In a paper published in the journal PLoS One on 24 September 2014, Victoria Arbour and Michael Burns of the Department of Biological Sciences at the University of Alberta, Robert Sulivan, Spencer Lukas and Amanda Cantrell of the New Mexico Museum of Natural History and Science, Joshua Fry of the Department of Geosciences at Fort Hays State University and Thomas Suazo, also of the New Mexico Museum of Natural History and Science describe a new species of Ankylosaurid Dinosaur from the Late Cretaceous Kirtland Formation at Hunter Wash in San Juan County, New Mexico.

The new species is named Ziapelta sanjuanensis, where ‘Zia’ refers to the stylised sun on the flag of New Mexico (which is derived from the Zia sun symbol of the indigenous Zia people of the state) and ‘pelta’ means a small shield, in reference to the animals osteoderms, while ‘sanjuanensis’ means ‘from San Juan’.Ziapelta sanjuanensis is described from an largely complete skull plus two partial cervical vertebrae (neck bones) and some fragmentary osteoderms.

Ziapelta sanjuanensis, complete skull. (A) Dorsal view; (B) ventral view; (C) anterior view; (D) occipital view; and (E) left lateral view. Abbreviations: asca, anterior supraorbital caputegulum; bas, basioccipital; ch, choana; fm, foramen magnum; j, jugal; laca, lacrimal caputegulum;loca, loreal caputegulum; ltf, laterotemporal fenestra; mnca, median nasal caputegulum; nar, externalnaris; oc, occipital condyle; orb, orbit; pal, palatine; par, parietal; parocc, paroccipital process; pmx, premaxilla; psca, posterior supraorbital caputegulum; pt, pterygoid; q, quadrate; qj, quadratojugal; qjh, quadratojugal horn; snca, supranarial caputegulum; socc, supraoccipital; sqh, squamosal horn; tr, tooth row; v, vomer. Arbour et al. (2014).

Speculative life restoration of Ziapelta sanjuanensis. Sydney Mohr in Arbour et al. (2014).

See also…

Nodosaurid teeth from the Early Cretaceous of southern England.

The Nodosaurids were a group of Ankylosaurid Dinosaurs that differed from other members of the group in having spines, rather than bony clubs, on the ends of their tails, and additional large spines on their...

A new species of Ankylosaurid Dinosaur from the Late Cretaceous of Montana.

The Ankylosaurids were large armoured Dinosaurs from the Cretaceous of Europe, Asia and North America...

New description of an Ankylosaurid Dinosaur from Mongolia.

The 1971 Polish-Mongolian Palaeontological Expedition to the Gobi Desert unearthed a great deal of dinosaurian material, including the partial skeleton of an...

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