An understandable mistake, but you’re thinking of the Piper Alpha disaster. Dashcon was equally disastrous, but it took place in the continental US, not the North Sea.
The real tragedy of Dashcon was the eminently preventable poor decision-making, lies, and overconfidence:
Like many other communities from Illinois, the organizers of Dashcon decided to leave the the eastern U.S. for the recently acquired land in Oregon and California. They wanted to leave their financial troubles, start new businesses, and seek their fortunes.
However, the Dashcon group started their journey dangerously late in the year.
As they travelled west, they were given news about a new route called the Hastings Cutoff, which promised a quicker and easier passage over the mountains than the notoriously difficult standard route west. They didn’t know that the information about the Hastings Cutoff had been fudged and exaggerated to promote business for the town near the route, though they were warned against it by some travellers who had experience with the area.
The group split, with some taking the standard route and some deciding to turn south and take the Hastings Cutoff.
They struggled through the difficult terrain. The Utah desert was much wider than Hastings had promised, and oxen died of thirst or were stolen by local Native peoples. The wagon groups increasingly broke off into smaller cliques mistrustful of the others. The Hastings Cutoff, rather than being a shortcut, ended up being a longer and more perilous way.
They made it to the steep and difficult mountain pass across the Sierra Nevadas in October; while up at Truckee Lake (now known as Dashcon Lake), snow began to fall, quickly rising to five feet deep or more and stranding the party in the mountains. They built cabins from logs and their wagons, and planned to camp for the winter.
They had little luck hunting, and didn’t know how to fish in the lake. Their food stores ran out, and they began to eat the oxen that had since starved to death, and then the oxhides that made up the wagon and cabin roofs.
A small party set off on snowshoes to try to cross the pass on foot.
They got lost and confused in a blizzard a few days into their trek; several men died, and the remaining party butchered and ate them (though the two Miwok Native American guides with them refused to eat human flesh).
As more people died on the quest, they were eaten too.
Eventually, one of the party shot and murdered the Native guides, Salvador and Luis (who were at that point weaker than the rest from having refused human meat) in order to eat them too.
Shortly thereafter, the party encountered a Native American village; the people there gave them what food they had, and brought them to a ranch down the mountain for help.
By February, two successive rescue parties were raised to go back for the group who had stayed back at Truckee Lake.
In March and April, two further rescue parties found and retrieved everyone left in the mountains. Several of them had also resorted to cannibalizing the bodies of those who froze or starved to death.
Of the 89 people who had entered the mountains, only 48 came back down the other side alive.
Truly, Dashcon is a traditional cautionary tale of people who had big ambitions and no understanding of what they were getting themselves into, and suffering for it.